Method and system for agricultural fertigation

ABSTRACT

An agricultural fertigation method includes the continuous charging of crop-quality-enhancer-feedstock comprised of one or more crop-quality enhancers (fertilizers, soil amendments and the like) to an irrigation system upstream of the agricultural field being irrigated. The crop-quality-enhancer-feedstock is diluted upon so charging to a level within the system solubility limits and the stream of flowing irrigation water dampens the resultant dissolution exotherm. A system wherein crop-quality enhancers are efficiently continuously fed to the irrigation system main line or a side-arm mixing chamber efficiently implements the method.

This application is a continuation in part of co-pending applicationSer. No. 13/385,736, filed Mar. 5, 2012, which is a continuation in partof application Ser. No. 13/136,032, filed on Jul. 21, 2011, which is acontinuation in part of application Ser. No. 12/283,448, filed on Sep.12, 2008, claiming the domestic priority benefit of application No.61/056,151 filed on May 27, 2008, inventors Miller et al., for Device,Composition and Method for Supplying Soil Amendments and Fertilizers toIrrigation Systems.

BACKGROUND OF THE INVENTION

The present invention relates to methods for adding crop-qualityenhancers, including but not limited to fertilizers, to agriculturalirrigation systems, including particularly agricultural micro-irrigationand sprinkler systems.

The agriculture industry has developed the practice of addingfertilizers to the plant environs, such as the soil, to enhance cropgrowth and subsequent yields. These fertilizers come in a variety offormulations depending on the specific crop to be grown and its nutrientrequirements.

Fertilizers generally are classified according to their NPK content. NPKis common terminology used in the fertilizer industry and stands for:(1) N—the amount of nitrogen in the formulation as N; (2) P—the amountof phosphorus in the formulation as P₂O₅; and (3) K—the amount ofpotassium in the formulation as K₂O. In other words, the N refers tonitrogen-containing compounds that are added to the soil and areutilized by the particular plant to satisfy its nitrogen requirement.The P refers to phosphorus-containing compounds that are added to thesoil and are utilized by the particular plant to satisfy its phosphorusrequirement (a nutrient required for plant growth). K refers topotassium-containing compounds that are added to the soil and areutilized by the particular plant to satisfy its potassium requirement(another nutrient essential for plant growth). Besides these basicnutrients or macronutrients, namely nitrogen, phosphorus and potassium,which are normally provided by the addition of fertilizers thattypically are known as NPK fertilizers, other minor nutrients(micronutrients) can also be provided by the addition of fertilizers tothe soil. Typical micronutrients are calcium, magnesium, sulfur, iron,zinc, manganese, copper, boron and molybdenum. The term “fertilizer” asused herein, unless expressly indicated otherwise, refers to NPKfertilizers, that is, fertilizers that include one of more of themacronutrients (nitrogen, phosphorus and potassium). An NPK fertilizermight, or might not, include or be combined (formulated) with materialsthat are added to the soil to provide micronutrient-containing compounds(micronutrient fertilizers).

As mentioned above, fertilizers contain macro and/or micro nutrients andit is these nutrients (“fertilizer nutrients”) that are taken up andutilized by the growing crops. A fertilizer, as that term is used hereinand as generally understood, refers to the nutrient-containing materialsthat are physically employed to deliver fertilizer nutrients to a crop.The fertilizer-nutrient content of fertilizers can range from very lowto very high. Conventional fertilizers typically (andlow-nutrient-content fertilizers always) will contain non-nutrientmaterials that are extraneous to the crop's nutrient-uptake(“nutrient-extraneous materials”), but for practical and/or otherreasons such non-nutrient materials may be necessary to the delivery ofthe nutrients. The process of delivering fertilizer nutrients to cropsis referred to as fertilization although, as explained here, fertilizerstypically contain nutrient-extraneous materials.

Growers added fertilizers centuries ago to grow better crops to feedincreasing populations, typically by simple mechanical addition(mechanical delivery) to the soil in which the crop was grown. Aspopulations increased further, irrigation of the land to improve cropsand crop yields became another common agricultural practice.Fertilization methods ultimately were facilitated by the practice ofadding fertilizers to the water being used to irrigate the crops. Theterm “fertigation” is used for this combination of irrigation andfertilization. Although extremely crude by today's standards, the earlyfertigation techniques provided higher crop yields and drasticallyreduced the labor expended in the addition of fertilizers.

Today's high demand for crops (food crops and otherwise) has turnedagriculture into a technically-sophisticated business, and a business inwhich large corporate farms dominate the small family farm. Thetechnical challenges faced by the modern agricultural industry includeboth the ever-increasing need for arable land, especially in the westernand southwestern United States, and the decreasing availability andincreasing cost of water. To conserve water, current conventionaltechnology includes micro-irrigation systems that deliver preciseamounts of water directly to the soil holding the root system of theplant that is being grown. In the past twenty to thirty years, a largepercentage of crop producers in the western and southwestern UnitedStates have converted from flood and sprinkler irrigation systems tomicro-irrigation technology. Micro-irrigation contains devices calledemitters, micro-sprinklers or other such devices that provide theprecise amounts of water directly to the desired soil site, namely thesoil holding the roots of the plant or crop being irrigated. Similar tothe advent of fertigation practices generally, upon conversion tomicro-irrigation systems, modern farmers began adding fertilizersthrough them.

Micro-irrigation systems, unfortunately, are sensitive to water qualityand the inclusion of fertilizers and other additives. The sensitivity ofmicro-irrigation systems to water quality and additives stems from therefinement of the micro components in a micro-irrigation system. Theseemitters, micro-sprinklers or other micro devices deliver the desiredprecise amounts of water so long as they do not plug or foul. Pluggingoccurs when deposits, from any source, build up inside these devices.The smallest particle or foreign material can cause fouling of thesedevices because these devices have very tiny orifices and/or a longtortuous narrow passageway that provide the requisite pressure fordelivery of precise amounts of water in a uniform manner to each plantin the crop being irrigated. Water quality and the inclusion offertilizers and other additives can, and frequently does, cause severeplugging problems. The problems arise from a number of factors: (1) theirrigation water is typically obtained from wells, reservoirs, canals,lakes, or rivers which contain various amounts of dissolved minerals;and (2) fertilizers, soil amendments and other additives can forminsoluble salts and/or cause particulate formation when added to thewater. Macro-irrigation systems mainly tolerate these conditions, whilemicro-irrigation systems are extremely intolerant.

In more detail, the addition of fertilizers or other materials, forinstance soil amendments, to the micro-irrigation water increases theloading of inorganic salts over that already in the water. When theloading, or the combined loading, is too high, the solubilities of atleast some of the naturally-occurring minerals and/or added compoundsare exceeded and particulate formation increases dramatically. Whenparticulates form, significant deposits begin to build up throughout theentire micro-irrigation system. The end result is plugging of theemitters or micro-sprinklers.

Plugging results in uneven distribution of water and nutrients to thecrop being irrigated. In some cases, complete shut-down of theirrigation system occurs. Therefore problem-free use of additives suchas fertilizers and/or soil amendments and the like in micro-irrigationsystems is normally seen only in irrigation systems that use relativelypure water sources.

Various methods for the mechanical delivery of fertilizers to the cropare of course still available. Fertilizers can simply be spread onto thesoil and mixed into the soil prior to planting the crop. Although thismethod of addition is still practiced today, especially in the case ofinexpensive NPK sources, such as salt peter (potassium nitrate),phosphate rock (calcium phosphate) and gypsum (calcium sulfatehexahydrate, which is a source of the micronutrients calcium andsulfur), this spread-and-mix-in method is extremely expensive due to thehigh cost of the equipment employed, the fuel consumed and laborrequired.

Another mechanical method is to place or deposit fertilizers, such assolid fertilizers, alongside (by the side of) the plant rows in thefield. This “side dressing” of additives is then plowed or tilled intothe area surrounding the roots of the plant. This method is considered a“root zone” application of fertilizers because it provides aconcentrated amount of fertilizer at or very close to the area at whichabsorption through the roots occurs, and it avoids fertilizing the areasbetween crop rows. Although this method reduces fertilizer usage (andthus fertilizer cost), the high equipment, fuel and labor costs remain.

Another mechanical delivery method of fertilizers is to sprayconcentrated aqueous solutions of fertilizers directed towards the rootzone instead of depositing solid fertilizers in the side dressingmethod. Spraying eliminates the need to plow and mix the solidfertilizer into the soil, but does not significantly reduce overallcosts because the spraying equipment is expensive and labor costsremain.

The fertigation process, in contrast, reduces the equipment, fuel andlabor costs associated with the various methods for the mechanicaldelivery of fertilizers to the crop. In conventional fertigationpractices, including micro-irrigation fertigation practices, commercialfertilizers are pumped directly into the irrigation system insingle-shot or “slug” feedings and delivered to the root system or rootzone together with the irrigation water that is already being suppliedto the crop. In comparison to mechanical delivery/distribution methods,fertigation achieves a significant overall cost savings.

The conventional agricultural practice is to make intermittent orperiodic applications of fertilizers. Such intermittent additions mightbe a single addition, or a plurality of additions, of large amounts(high concentrations) of fertilizer during a brief time interval eachgrowing season or crop cycle. (The number of applications per growingseason or crop cycle usually depends on the crop and/or the type offertilizer being added.) When the fertilizer-delivery method isfertigation, fertilizers are typically slug fed into the irrigationsystem as quickly as possible to minimize the labor requirements andease material handling. Slug feeding of a block (portion of a field)normally entails feeding the large amounts (high concentrations) offertilizer to the irrigation water over a six to seven hour periodduring irrigation, and then, after the fertilizer feed is shut off,continuing the irrigation of that block for an additional two to threehours to rinse out all of the fertilizer that is contained inside theirrigation system, insuring that all of the fertilizer intended for theblock is in fact delivered to the block.

The cost of commercial fertilizer formulations is, however, itselfsignificant, and commercially viable fertilizer formulations(formulations sufficiently inexpensive for bulk agricultural use)typically include, as mentioned above, nutrient-extraneous materialswhich do not contribute to plant nutrition, and can even be undesirablecomponents.

SUMMARY OF THE INVENTION

The present method is directed to fertigation wherein acrop-quality-enhancer feedstock is charged to an active irrigationsystem continuously, or substantially continuously, at very low levels,during the entire time, or substantially the entire time, thatirrigation water is sufficiently flowing through the irrigation systemfor a prolonged term. The feedstock is comprised of at least one, and inembodiments includes a plurality of, crop-quality enhancers (feedstockcomponents) that intermix as the feedstock is charged to the irrigationsystem, and in further embodiments the feedstock explicitly includes oneor more micronutrients (micronutrient-augmented crop-quality-enhancerfeedstock) such as iron, manganese, zinc, magnesium, boron, copper,molybdenum and cobalt. The present invention provides a method and/orsystem for fertigation wherein a crop-quality-enhancer feedstock (rawmaterials or inputs), which in some embodiments includes fertilizers(commercial or otherwise, and including fertilizer-nutrient feedstocks),is charged to an active irrigation system continuously, or substantiallycontinuously, at very low levels, during the entire time, orsubstantially the entire time, that irrigation water is sufficientlyflowing through the irrigation system, for a prolonged term(“prolonged-termed continuous charge” or “prolonged-termed continuousfertigation”) via a system that provides a high-dilution environment inthe feedstock-component intermixing zone. The present method does notexclude on-site fertilizer production (manufacture) from the feedstockas that feedstock is charged to the irrigation system continuously, orsubstantially continuously, at very low levels, during the entire time,or substantially the entire time, that irrigation water is sufficientlyflowing through the irrigation system, whereby an enhanced fertilizer isproduced that has a higher fertilizer-nutrient content (low or minimalnutrient-extraneous material) and that is flexible as to the type ofnutrient so as to be readily customized to a crop's nutrient needsand/or growing conditions, which are advantages that are not availablefrom conventional fertilizers. In preferred embodiments, the system ofthe present invention is automatic and subject to variation of theamount and type of crop-quality enhancers forming the feedstock asdesired.

The term agricultural “crop-quality enhancer” as used herein is acomprehensive term or descriptor for soil amendments, fertilizers and pHmodifiers because they all enhance (improve, boost, add to) the qualityof the crop, including the quantity of crop yields. A fertilizerprovides plant nutrients and thereby enhances the quality of the crop. Asoil amendment or soil modifier changes or improves the soil structurewhereby the crop is better enabled to utilize or take up water andnutrients in the soil. A pH modifier internally cleans, or maintains theinternal cleanliness of, the irrigation system, whereby irrigation wateris distributed uniformly and without the distribution gaps caused byplugged lines, emitters and the like. A pH modifier also may optimizethe pH such that certain nutrients are more readily available to thecrop plants and thereby enhance the quality of the crop. Each of thesefunctional modes promotes crop health, growth and productivity,including reduction of crop losses due to insufficient irrigation. Inother words, each of these functional modes promotes the quality of thecrop. The crop-quality enhancer of the present invention typicallyenhances an agricultural crop in more than one mode. Typically, but notnecessarily, all three crop-quality enhancements are realized at leastto some degree in the various embodiments of the invention. The term“micro-irrigation” as used herein and in the claims refers tomicrosprinkers, drip, and subsurface drip systems.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is an at least partially diagrammatic view of a system of thepresent invention.

FIG. 2 is an at least partially diagrammatic view of a section of thesystem of FIG. 1.

FIG. 3 is an at least partially diagrammatic view of a section of thesystem of FIG. 1.

FIG. 4 is an at least partially diagrammatic view of a section of asystem of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Prolonged Term:

By prolonged term is meant herein a time period that extends from aninterval (term) during a crop cycle comprising at least multipleconsecutive irrigations, and preferably comprising at least a threemonth time period or a time period comprising fifty percent of therespective crop cycle, and more preferably at least a four month timeperiod or a time period comprising seventy-five percent of therespective crop cycle, up to ninety percent of the respective crop cycleor even an entire crop cycle. (A crop cycle is a crop's growing period,from embryonic to maturity or harvest, during which the crop isirrigated.) Since potassium promotes fruiting (fruit development), thatis, the ripening of a crop plant's fruit, when such ripening is at, orapproaches, optimal, potassium fertilization normally is ceased to avoidfruit development beyond the point that provides the crop's bestagronomic output (agronomic payload or payout), such as fruit,vegetable, nut and the like sections of the plant, prior to harvest.

Continuous Fertigation

The method and/or system of the present invention, namely the methodand/or system for fertigation by charging a crop-quality-enhancerfeedstock which includes one or more crop-quality enhancers, to theirrigation system, drastically reduces costs and labor in comparison toconventional fertigation techniques, drastically is far more flexibleand controlled as to the crop-quality enhancers provided and in someembodiments reduces the extraneous material in the crop-qualityenhancers delivered to the crops, in comparison to conventionalfertigation and other fertilization and/or soil amendment practices andtechniques.

Depending on the crop-quality enhancer(s) being added, the presentinvention may reduce the number of undesirable components being added(nutrient-extraneous material) in comparison to the undesirablecomponents that will normally be added with conventional fertigation. Acomponent is undesirable when it interferes with, or is otherwisedetrimental to, the fertigation process, such as a species which lowersthe system solubility ceiling, or creates an excess of a nutrient, or istoxic to the crop, or is superfluous or the like.

The in-situ fertilizer formulation or manufacture embodiment of thepresent invention generally, in combination with the continuous lowlevel addition of the crop-quality-enhancement method of the presentinvention, will further reduce the labor and the plugging potentialdrawbacks of conventional fertigation.

The crop-quality-enhancer feedstock used in certain embodiments of theinvention is selected from eight basic crop-quality enhancers, namelysulfuric acid, nitric acid, phosphoric acid, potassium hydroxide, urea,calcium nitrate, magnesium nitrate and ammonium hydroxide. Thesecrop-quality enhancers are typically not, or cannot be, currently addedto an irrigation system. (The crop-quality-enhancer feedstock used inthe present invention may be other than these eight crop-qualityenhancers, and may include commercial fertilizers.)

Sulfuric Acid

If concentrated sulfuric acid was added to the irrigation system,without the control provided by the present on-site manufacturingsystem, the following problems would be encountered by the grower. (1)The irrigator would be required to handle a very corrosive material thatnecessitates special equipment and safety precautions. (2) Specialhandling techniques must be employed because adding sulfuric acidcreates a risk of (a) corrosion of the metal components of theirrigation system and (b) embrittlement of, and damage to, the sensitiveplastic irrigation-system components (emitters and the like) thatdeliver regulated amounts of water to each plant. When sulfuric acid isadded to an irrigation system in conventional agricultural practices,for instance for soil amendment purposes (sulfuric acid has no NPKnutrients) or cleaning to remove scale, the addition is typically doneby an outside provider as a service due to the hazardous properties andthe supervision that is required for its addition.

Nitric Acid

Nitric acid has the same safety and handling problems, and the samecorrosion and embrittlement problems, as described above for sulfuricacid. In addition, despite its N nutrient content, it is never used as afertilizer because its nitrogen is only nitrate nitrogen. Nitratenitrogen is immediately absorbed by a plant and for agronomic reasons amixture or blend of nitrate and ammoniacal nitrogen is desirable. Nooutside companies supply nitric acid to agriculture for directapplication because of its hazardous properties, its lack of a balancedblend of suitable nitrogen and the outside supervision that would berequired for its addition.

Phosphoric Acid

Phosphoric acid has the same, although less severe, safety and handlingproblems, and the same corrosion and embrittlement problems, asdescribed above for sulfuric acid. Growers do occasionally feedphosphoric acid as a cleaner or (infrequently) as a phosphorus source.To obtain the requisite amount of phosphorous as P, the grower typicallyinstead uses blends of potassium and/or ammoniacal phosphate solutionswhich are easier to handle, but more expensive than phosphoric acid.

Potassium Hydroxide

Potassium hydroxide is never used in agriculture due to its causticnature (high alkalinity) which results in safety and handling problemsfor the grower. The high alkalinity, in combination with the typical lowquality of typical irrigation water, leads to calcium and/or magnesiumcarbonate precipitation, which plugs the irrigation system. The highalkalinity also leads to soil “hardpanning” (forming a rock-hard barrierthat water cannot penetrate) upon interaction with the soil.(Hardpanning is one of the reasons acidic soil amendments are added attimes to the irrigation water.) Potassium salts are instead utilized asa conventional potassium source despite their much higher costs.

Urea

Urea, a very slow release source of nitrogen (N), is rarely used as afertilizer itself. Instead, because growers prefer a more predictableprofile of the release of nitrogen, they normally use a blend ofnitrogen sources. The most common nitrogen-source fertilizer blend iscalled UAN-32. (UAN is an acronym for an aqueous solution of urea andammonium nitrate.) UAN-32 is a blend of ammonium nitrate and urea(sometimes referred to as “urea ammonium nitrate”), which contains 32.0%nitrogen (as N), namely 7.75% ammoniacal nitrogen (slow releasenitrogen), 7.75% nitrate nitrogen (fast release nitrogen), and 16.5%urea nitrogen (very slow release nitrogen). Nitrate nitrogen is utilizedby the plant directly and therefore is considered a fast release sourceof nitrogen. Ammonia, ammonic or ammoniacal nitrogen, considered aslow-release form of nitrogen, first must be oxidized or fixed in thesoil to form nitrate, which can then be used by the plant. Urea,considered a very slow or controlled-release form of nitrogen, must behydrolyzed in the soil to form ammonia and carbon dioxide and then fixedto form nitrate, before it can be used by the plant and is considered avery slow or controlled release form of nitrogen. A common alternativeto an UAN-32 blend is AN-20, an ammonium nitrate solution. (AN is anacronym for an aqueous solution of ammonium nitrate.) In either case,these commercial products are supplied as very dilute solutions (whichcreates high shipping costs) and are expensive.

Calcium Nitrate

Calcium nitrate (a non-co-reactant crop-quality enhancer), a nitrogensource of the rapid-release nitrate form, is rarely used by growers.Instead, if both calcium and nitrogen were needed for the crop, andbecause growers prefer a more constant (“uniform”) release of nitrogen,the grower would use a product called CAN-17. (CAN is an acronym for anaqueous solution of calcium nitrate and ammonium nitrate.) CAN-17 is ablend of calcium nitrate and ammonium nitrate (sometimes referred to as“calcium ammonium nitrate”) which contains 17.0% nitrogen (as N), namely5.4% ammoniacal nitrogen (slow-release nitrogen) and 11.6% nitratenitrogen (fast-release nitrogen), and 8.8% calcium (Ca). CAN-17 is avery dilute solution (which creates high shipping costs) and isexpensive. Another source of calcium that is frequently used by a groweris gypsum (calcium sulfate hexahydrate). This calcium source is verydifficult to add through the irrigation system because of its limitedwater solubility (grower must use specialized gypsum machines foraddition). Addition of gypsum can cause severe plugging of theirrigation system. It is mainly used as a soil amendment and less so asa calcium source, particularly since it does not contain any nitrogenwhich the grower must add anyways. If used, to overcome the solubilityissues the trend has been to field spread the gypsum which is veryequipment and labor intensive.

Magnesium Nitrate

Fertilizer companies conventionally do not offer magnesium nitrate (anon-co-reactant crop-quality enhancer) as a standard product. Toovercome soil magnesium deficiencies, growers typically field-spreaddolomite, a naturally occurring mineral which is a 1 to 1 mixture ofcalcium and magnesium carbonate. Unfortunately, a ratio of about 4 to 1of calcium to magnesium is optimal for plant growth and therefore agrower who field-spreads dolomite is “out-of-balance” in terms of thedesired calcium/magnesium ratio. Further, although dolomite is a cheapmagnesium source despite its low per-pound magnesium content,field-spreading is very equipment and labor intensive.

Ammonium Hydroxide

Ammonium hydroxide is never used in agriculture due to its causticnature which results in safety and handling problems for the grower. Thehigh alkalinity, in combination with the typical low quality of typicalirrigation water, leads to calcium and/or magnesium carbonateprecipitation, which plugs the irrigation system. The high alkalinityalso leads to soil “hardpanning” (forming a rock-hard barrier that watercannot penetrate) upon interaction with the soil. (Hardpanning is one ofthe reasons acidic soil amendments are added at times to the irrigationwater.) In the practice of the method of the present method, ammonia gasdissolved in water on-site to produce ammonium hydroxide can be used.

Further, one or more of the following twenty-three fertilizers might beproduced according to the chemical reactions shown below when thefeedstock includes sulfuric acid, phosphoric acid, nitric acid,potassium hydroxide, urea, ammonium hydroxide (or ammonia), calciumnitrate and/or magnesium nitrate, and the present invention does notexclude the addition of one or more of the acids (or hypothetically oneor more of the bases) on the list for the purpose of pH adjustment,regardless of whether or not such acid (or base) is a co-reactant whenit intermixes with the other crop-quality enhancers.

Potassium nitrate, produced from nitric acid and potassium hydroxide,Eq. 1.HNO3+KOH→KNO3+H2O  (Eq. 1)

Potassium sulfate, produced from sulfuric acid and potassium hydroxide,Eq. 2.H2SO4+2KOH→K2SO4+2H2O  (Eq. 2)

Potassium hydrogen sulfate, produced from sulfuric acid and potassiumhydroxide, Eq. 3.H2SO4+KOH→KHSO4+H2O  (Eq. 3)

Potassium ammonium sulfate, produced from sulfuric acid, potassiumhydroxide and ammonium hydroxide or ammonia, Eq. 4a, 4b.H2SO4+KOH+NH4OH→K(NH4)SO4+2H2O  (Eq. 4a)H2SO4+KOH+NH3→K(NH4)SO4+H2O  (Eq. 4b)

Potassium phosphate (mono-H) produced from phosphoric acid and potassiumhydroxide, Eq. 5.H3PO4+2KOH→K2HPO4+2H2O  (Eq. 5)

Potassium phosphate (di-H) produced from phosphoric acid and potassiumhydroxide, Eq. 6.H3PO4+KOH→KH2PO4+H2O  (Eq. 6)

Potassium phosphate produced from phosphoric acid and potassiumhydroxide, Eq. 7.H3PO4+3KOH→K3PO4+3H2O  (Eq. 7)

Potassium ammonium phosphate (mono-NH4 and mono-K) produced fromphosphoric acid, ammonium hydroxide (or ammonia) and potassiumhydroxide, Eq. 8.H3PO4+NH4OH+KOH→KH(NH4)PO4+2H2O  (Eq. 8)

Potassium ammonium phosphate (di-NH4 and mono-K) produced fromphosphoric acid, ammonium hydroxide (or ammonia) and potassiumhydroxide, Eq. 9.H3PO4+2NH4OH+KOH→K(NH4)2PO4+3H2O  (Eq. 9)

Potassium ammonium phosphate (mono-NH4 and di-K) produced fromphosphoric acid, ammonium hydroxide (or ammonia) and potassiumhydroxide, Eq. 10.H3PO4+NH4OH+2KOH→K2(NH4)PO4+3H2O  (Eq. 10)

Urea nitrate produced from urea and nitric acid, Eq. 11.H2NCONH2+HNO3→(H2NCONH2)(HNO3)  (Eq. 11)

Urea phosphate produced from urea and phosphoric acid, Eq. 12.H2NCONH2+H3PO4→(H2NCONH2)(H3PO4)  (Eq. 12)

Dicarbamide dihydrogen sulfate (equivalent of N-pHURIC® 28/27; N-pHURIC®is a registered trademark of Union Oil Company of California dba UnocalCorporation California of El Segundo, Calif.) produced from urea andsulfuric acid, Eq. 13.2H2NCONH2+H2SO4→(H2NCONH2)2(H2SO4)  (Eq. 13)

Monocarbamide dihydrogen sulfate (equivalent of N-pHURIC® 15/49;N-pHURIC® is a registered trademark of Union Oil Company of Californiadba Unocal Corporation California of El Segundo, Calif.) produced fromurea and sulfuric acid, Eq. 14.H2NCONH2+H2SO4→(H2NCONH2)(H2SO4)  (Eq. 14)

Urea ammonium nitrate (UAN-32) produced from urea, ammonium hydroxide(or ammonia) and nitric acid, Eq. 15.H2NCONH2+NH4OH+HNO3→(H2NCONH2)((NH4)NO3)+H2O  (Eq. 15)

Ammonium nitrate (AN-20) produced from ammonium hydroxide (or ammonia)and nitric acid, Eq. 16.NH4OH+HNO3→(NH4)NO3+H2O  (Eq. 16)

Ammonium sulfate produced from ammonium hydroxide (or ammonia) andsulfuric acid, Eq. 17.2NH4OH+H2SO4→(NH4)2SO4+2H2O  (Eq. 17)

Ammonium hydrogen sulfate produced from ammonium hydroxide (or ammonia)and sulfuric acid, Eq. 18.NH4OH+H2SO4→(NH4)HSO4+H2O  (Eq. 18)

Ammonium phosphate (mono-H) produced from ammonium hydroxide (orammonia) and phosphoric acid, Eq. 19.2NH4OH+H3PO4→(NH4)2HPO4+2H2O  (Eq. 19)

Ammonium phosphate (di-H) produced from ammonium hydroxide (or ammonia)and phosphoric acid, Eq. 20.NH4OH+H3PO4→(NH4)H2PO4+H2O  (Eq. 20)

Ammonium phosphate produced from ammonium hydroxide (or ammonia) andphosphoric acid, Eq. 21.3NH4OH+H3PO4→(NH4)3PO4+3H2O  (Eq. 21)

Calcium ammonium nitrate (CAN-17) produced from ammonium hydroxide (orammonia), nitric acid and calcium nitrate, Eq. 22.2NH4OH+2HNO3+Ca(NO3)2→(Ca(NO3)2)(NH4NO3)2+2H2O  (Eq. 22)

Magnesium ammonium nitrate produced from ammonium hydroxide (orammonia), nitric acid and magnesium nitrate, Eq. 23.2NH4OH+2HNO3+Mg(NO3)2→(Mg(NO3)2)(NH4NO3)2+2H2O  (Eq. 23)

The other aspect of the method and/or system of the present invention,namely the method and/or system for fertigation whereincrop-quality-enhancer feedstock is charged to the irrigation systemcontinuously or substantially continuously at very low levels,drastically reduces the labor involved, eliminates fouling and pluggingpotential, and provides a uniform, consistent level of nutrientavailability throughout a crop cycle, in comparison to conventionalfertigation techniques.

Conventional Fertigation Methods and the Labor Drawback

In conventional fertigation methods, bulk fertilizer formulations aredelivered to individual storage tanks at the grower's site. From there aperson referred to as an irrigator may further fill a smaller tank or“nurse tank” with one of the fertilizer formulations and transfers thatparticular nurse tank to the irrigation water pump site. The irrigatorthen turns on the irrigation water, connects a feed pump to theirrigation system and then lets the fertilizer formulation slug feed(rapidly add) from the nurse tank to the irrigation water over a periodof approximately six to seven hours. When the target amount offertilizer has been added to the irrigation system in this manner, theirrigation water must then continue to flow for typically two to threehours to thoroughly flush the fertilizer from the irrigation system.Depending on the number of “sets” or areas (or blocks) of the field thatare to be fertigated, this process might be conducted two or three timesper day by one or more irrigators. At the end of the day theirrigator(s) must clean the feed pump(s) and nurse tank(s) Depending onthe number of sets associated with an irrigation pumping site, theentire process, including cleaning the fertilizer feed pump and nursetank, and filling/transporting the nurse tank, might be repeated for twoor three days or longer for a given fertilizer formulation. During agrowing season or cycle, the entire process may be repeated one or moretimes for a given fertilizer formulation. Additionally, the entireprocess described above is performed separately for each fertilizerformulation which is added to the crop. As seen from these descriptions,the conventional method of fertigation is very labor intensive.

Conventional Fertigation Methods and the Plugging-Potential Drawback

In conventional fertigation methods, the slug feeding of variousfertilizer formulations can cause substantial plugging of the irrigationsystem. This type of plugging occurs when impurities contained in theirrigation water interact with the fertilizer being slug fed. Thesolubility of one or more components of fertilizer and one or more ofthe impurities of the irrigation water is exceeded and one or moreinsoluble salts are formed and precipitate. This precipitate then plugsthe various parts of the irrigation system, particularly the emittersand/or micro-sprinklers.

In more detail, most naturally-occurring waters contain dissolvedminerals that can lead to plugging in micro-irrigation systems.Irrigation water constituents such as calcium, magnesium, alkalinity,iron, manganese, sulfates, and sulfide can precipitate to clog emitterflow, causing plugging. Water bicarbonate alkalinity concentrationsexceeding about 2 meq/liter (200 ppm as CaCO₃) can cause calciumcarbonate precipitation. Calcium concentrations exceeding 2-3 meq/liter(100-150 ppm as CaCO₃) can cause precipitates to form during theinjection of phosphate fertilizers. The Solubility Chart below providesan overview of inorganic anion/cation incompatibilities, that is, anionsand cations that, when both are present, lead to insoluble inorganicsalt formation that can cause plugging in micro-irrigation systems.

CHART 1 Solubility Chart For Common Irrigation-Systems Anions AndCations Anion Cation Cl HCO₃ ⁻ OH⁻ NO₃ ⁻ CO₃ ⁻² SO₄ ⁻² S⁻² PO₄ ⁻³ Na⁺ SS S S S S S S K⁺ S S S S S S S S NH₄ ⁺ S S S S S S S S H⁺ S S H₂O S CO₂S H₂S S Ca⁺² S SS VSS S I VSS XXX I Mg⁺² S S I S VSS S XXX I Fe⁺² S SSVSS S VSS S I I Fe⁺³ S I I S I S XXX I Mn⁺² S XXX I S I S I I

In Chart 1, S means soluble (over 5,000 ppm), SS means slightly soluble(2,000 to 5,000 ppm), VSS means very slightly soluble (20-2,000 ppm), Imeans insoluble (<20 ppm) and XXX means does not form (is not acompound). From Kemmer, Frank N., Water: The Universal Solvent, BasicChemistry, p. 37, Nalco Chemical Company 1977.

As seen from the solubility information in Chart 1, the addition ofphosphates, such as phosphate fertilizers, to naturally-occurring watersthat contain hardness (cationic calcium or magnesium) can causeprecipitation that would result in the plugging of micro-irrigationsystems. Also as seen from the solubility information in Chart 1 thereare many incompatibilities that can be problematic for irrigationwaters, let alone for a combination of irrigation waters to whichfertilizers and micronutrients have been added. As mentioned above,hardness, namely calcium (Ca⁺²) and magnesium (Mg⁺²) cations, in thepresence of alkalinity, namely bicarbonate (HCO₃ ⁻), carbonate (CO₃ ⁻²)and hydroxide (OH⁻) anions, can combine to form harmful precipitates,even in unmodified irrigation water. This situation is exacerbated whenmaterials such as gypsum (calcium sulfate hexahydrate, CaSO₄.6H₂O) orammonium phosphate fertilizer (a mixture of (NH₄)₂HPO₄ and (NH₄)H₂PO₄are slug fed to the irrigation water. In the case of slug-feedinggypsum, the additional loading of calcium cation triggers aprecipitation leading to plugging because, when irrigation watercontains hardness and/or alkalinity, more precipitate will form upon anincrease in one of the hardness or alkalinity components, regardless ofwhether the component is anionic or cationic. In the case ofslug-feeding of phosphate fertilizer, the addition of phosphate anionleads to the formation of insoluble calcium and magnesium phosphateswhen the irrigation water contains hardness.

Conventional Fertigation Methods and the Unbalanced NutrientAvailability Drawback

As discussed above, the conventional method of fertilizer addition, byfertigation or mechanical means, involves adding the fertilizer aboutonce or twice a growing season or crop cycle because of the logisticsand labor that are required. When the fertilizer is accordingly slug fedto the field, it is typically fed at a very high rate over a shortperiod of time, whereby a high concentration of fertilizer is added tothe root zone of the crop. This high concentration of fertilizer isgreater than the plant can absorb, and therefore it is not completelyabsorbed (which is why it is a “nutrient-extraneous material”). Some ofthe residual (non-absorbed) fertilizer, which typically is a highfertilizer residual, interacts with the soil. These fertilizer-soilinteractions normally result in the formation of insoluble inorganicsalts and non-exchangeable soil particles, with a concomitant andsubstantially irreversible loss of available fertilizer. Further, eachsubsequent irrigation drives or washes available residual fertilizeraway from the wetted root zone core towards the perimeter of the wettedzone, mechanically diminishing its availability to the plant.Eventually, the fertilizer concentration gradient which is createdresults in very little fertilizer being available within the wetted rootzone. The level of available residual fertilizer in the wetted root zonewill typically drop to essentially zero for a time period ahead of thenext fertigation. For these reasons, conventional fertigation practiceslead to huge swings in the amount of fertilizer that is available to theplant over time. These swings in available fertilizer in turn lead tocostly compensations in the form of increased fertilizer feeds. In otherwords, the amount of fertilizer that is considered required is increasedbecause a significant portion of the residual fertilizer becomesunavailable to the plant.

The Basics of the Present Fertigation Method and System

The crop-quality-enhancer feedstock is charged to an irrigation systemby concomitantly feeding its components (one or more crop-qualityenhancers, also referred to herein as raw materials) to either (1) awater stream (preferably a stream of irrigation water) flowing through amixing chamber that discharges to a main line of an irrigation systemdownstream of any irrigation-system filters and upstream of the deliverypoints of the irrigation system, or (2) directly to a main line of anirrigation system downstream of any irrigation-system filters andupstream of the delivery points of the irrigation system. Theintermixing of crop-quality enhancers, and any reaction(s), for instancereactions by which the fertilizers are produced therefrom, initiateeither in such a mixing chamber upstream of the irrigation system's mainline or within the main line itself.

The present method and system of the present invention preferably employan automated feed system which simultaneously feeds or charges one or aplurality of crop-quality enhancers to the mixing chamber or main lineat a pre-selected or pre-determined rate. Such an automated feed systemtherefore charges a crop-quality-enhancer feedstock of a pre-selected orpre-determined composition at a pre-selected or pre-determined rate. Theautomatic feeding of the crop-quality-enhancer feedstock at apre-selected or pre-determined rate is particularly important when it isdesirable to feed the feedstock at a rate relative to theirrigation-water flow rate, so as to automatically provide and maintaina pre-selected or pre-determined concentration of each crop-qualityenhancer in the irrigation water throughout the fertigation period,including when the irrigation water flow rate varies from one set to thenext. Such an automated feed system would be inactive or idle when thereis no irrigation water flow in the irrigation line served by theautomated feed system. That automated feed system may be, and in certainembodiments is preferably, automatically activated or triggered upon thecommencement of water flow in the irrigation line, and may be, and incertain embodiments is preferably, automatically deactivated or haltedwhen the flow of irrigation water ceases.

The charge of the crop-quality-enhancer feedstock to the irrigationwater is at a very low level feed so as to restrict or confinecrop-quality enhancer concentration in the irrigation water to extremelylow levels at all times. The charge of the crop-quality-enhancerfeedstock to the irrigation water is prolonged-termed continuous. By aprolonged-termed (or prolonged-term) continuous charge ofcrop-quality-enhancer feedstock (or continuously charging acrop-quality-enhancer feedstock over a prolonged term) is meant hereinthat the charge is continuous when irrigation water is sufficientlyflowing to dampen the dissolution, and any reaction, exotherms thatresult from the charge, or in other words, substantially continuousthroughout the irrigation cycles or continuous when the irrigationsystem is active for a term of at least multiple consecutive irrigationdays up to all of the irrigation days of an entire crop cycle. In moredetail, when an irrigation system is idled, water usually drains out andthe system becomes mainly filled with air. Upon reactivation, there is atime delay between the start of water flowing into the irrigation systemand the point of time at which the system reaches its operating pressure(from about 10 to 150 psi depending on the system). The continuouscharge of crop-quality-enhancer feedstock ceases when the shut down (theidling) of the irrigation system initiates and does not recommence untilat least a preponderance of the irrigation system is refilled withwater, at which point the system is typically approaching but might notyet be at its full operating pressure. The water-flow characteristicsrequired to dampen the dissolution, and any reaction, exotherms can becalculated using simple thermodynamics for any given irrigation system.

The Present Fertigation Method and the Alleviation of the Labor Drawback

The method and system of the present invention preferably employ one ormore smaller bulk tanks, positioned or located at the irrigation pumpingstation. Such bulk tanks are larger than the nurse tanks and smallerthan the storage tanks which hold conventional bulk fertilizers. When aplurality of bulk tanks are positioned at a given irrigation station,they may, and preferably do, each hold a different crop-qualityenhancer. The method and system of the present invention feeds acrop-quality-enhancer feedstock comprising one or a plurality ofcrop-quality enhancers to the irrigation water by simultaneous feedingfrom one or a plurality of bulk tanks. The automated feed system incertain embodiments may be set to automatically shut off either at apre-set time or when an irrigation period to the irrigation line beingserved by the automated feed system is over and the irrigation waterstops flowing. In all embodiments of the present invention, labor isdrastically reduced in comparison to conventional fertigation methods.While bulk raw materials for the crop-quality-enhancer feedstock underthe present invention would usually still be delivered to individualstorage tanks at the grower's site, most of the tasks conventionallyperformed by an irrigator, or person(s) handling the role of anirrigator, are eliminated. (1) The filling of a smaller tank or “nursetank” with one of the conventional or commercial fertilizer formulationsand the transferring of that particular nurse tank to the irrigationwater pump site for each irrigation period is eliminated, becauseinstead bulk tanks for each raw material of the crop-quality-enhancerfeedstock are in-place at the irrigation water pump site and such bulktanks normally require filling no more than once, namely at thebeginning of a growing cycle. (2) The crop-quality-enhancer feedstockpump is continuously connected to the irrigation system and is, or canbe, automatically triggered when irrigation-water flow commences, andtherefore, when the irrigator turns on the irrigation water: (a) he doesnot connect a commercial fertilizer feed pump to the irrigation systemfor each irrigation set; (b) he does not slug feed commercial fertilizerfor any amount of time (and therefore he does not need to start,maintain, stop and time a slug feed); and (c) he does not flush thecommercial fertilizer from the irrigation system or conduct day-endcleaning of the feed pump and nurse tank. (3) Additionally, the entireconventional process(s) described above is normally performed separatelyfor each conventional commercial fertilizer formulation which is addedto the crop, and therefore the tremendous labor savings as a result ofthe elimination of these steps is multiplied. (4) In addition, thefurther, and typically greater, labor expenditures involved whenremediation and repair of the irrigation system is required due to theplugging that may occur when conventional fertigation methods are usedare also eliminated.

In addition, because the present invention eliminates any pluggingpotential, as discussed below, there is no labor required to clean theirrigation system due to any plugging of the irrigation system.

The Present Fertigation Method and Alleviation of the Plugging-PotentialDrawback

Plugging of the irrigation system due to the formation and precipitationof insoluble salts is totally eliminated by the method and system of thepresent invention because the charge of the crop-quality-enhancerfeedstock continuously at very low levels keeps such precipitates fromforming. In other words, the charge of crop-quality-enhancer feedstockin the method and system of the present invention is at a rate thatprovides a component concentration in the irrigation water below theconcentration which would trigger precipitate formation, including butnot limited to precipitate formation due to irrigation water quality.

In contrast to the slug feeding of various fertilizer formulations whichcan cause substantial plugging of the irrigation system when impuritiescontained in the irrigation water interact with the fertilizer beingslug fed because the solubility of one or more components of fertilizerand one or more of the impurities of the irrigation water is exceeded,such solubilities are not exceeded in the present method because thefeed rate maintains the requisite low concentration of components.Insoluble salts cannot be formed. There is no precipitate that couldplug any of the various parts of the irrigation system.

The Present Fertigation Method and Alleviation of the UnbalancedNutrient Availability Drawback

In contrast to huge swings in available fertilizer when the fertilizeris slug fed about once or twice during a crop cycle, in the presentmethod when one or more fertilizer crop-quality enhancers are beingadded, the crop-quality-enhancer feedstock is added continuously at avery low level. A low level of the fertilizer crop-quality enhancer ispresent in almost every drop of irrigation water. This results in adramatic increase in the continuum or continuity of the availability offertilizer to the plant in comparison to the traditional slug-feedapproach for several reasons. Instead of a slug-fed addition of a highconcentration of fertilizer at the root zone of the crop, a very lowconcentration of fertilizer is delivered over any given irrigationcycle. This concentration is sufficiently low to be completely, oralmost completely, absorbed by the plants. There is little or noresidual (non-absorbed) fertilizer to interact with the soil and therebybecome unavailable due to the formation of insoluble inorganic salts andnon-exchangeable soil particles. Further, there is little or no residualfertilizer that can be washed away from the root zone upon subsequentirrigations, and each subsequent irrigation adds another low level offertilizer to the root zone. Therefore the level of available fertilizerin the wetted root zone will remain substantially uniform over theentire crop cycle. There will be no swings in the amount of fertilizerthat is available to the plant over time. There will be nolost-fertilizer compensations in the form of increased fertilizer feeds.The amount of fertilizer that is considered required is not increasedbecause, in the method and system of the present invention, essentiallylittle or no fertilizer becomes unavailable to the plant.

Low Level of Crop-Quality Enhancer

A low (sometimes referred to herein as a very low) level of crop-qualityenhancer (or of crop-quality-enhancer feedstock, or its feed or charge),as that terminology is used herein, means a level below that at whichinsoluble precipitates could form due to the solubility of any feedstockcomponent and/or irrigation-water component being exceeded. In otherwords, a low level is at or below the system solubility ceiling, thatis, within the system solubility limits. In preferred embodiments thelow level is also a dual-role level that does not exceed the systemsolubility ceiling and yet meets the minimum continuous-deliverycrop-quality enhancer requirement which is the crop-quality enhancer,particularly fertilizer, required to be continuously fed to theirrigation water throughout the cycle, or during a prolonged term, tomeet the feed or nutrient profile (the feed or nutrients deemednecessary or desirable for a given crop at a given site). In otherwords, for a given crop and site, the low level of crop-qualityenhancers, such as fertilizer, is preferably below the system solubilitylimits and at the minimum continuous-delivery crop-quality enhancerrequirement (or a deviation of 10 percent thereof), and the factors thatdetermine it are: (1) the quality of the irrigation water which will beused to irrigate the field in terms of its impurities; (2) crop-qualityenhancer, such as fertilizer, type; (3) the particular nutrient and/orother crop-quality enhancer requirements of the subject field; and (4)the total amount of irrigation water which will be delivered to field inthe given crop cycle. Factors (1) and (2) determine the systemsolubility ceiling and system solubility limits, and factors (3) and (4)determine the minimum continuous-delivery crop-quality enhancerrequirement. Typically there is a wide margin between the systemsolubility ceiling and the minimum continuous-delivery crop-qualityenhancer requirement point. Further, while there generally is nopractical or economical reason to use a level of fertilizer and/or othercrop-quality enhancer that is higher than the minimumcontinuous-delivery crop-quality enhancer requirement, in broadembodiments of the present invention, the low level of fertilizer and/orother crop-quality enhancer can significantly exceed the minimumcontinuous-delivery crop-quality enhancer requirement, provided ofcourse that the low level does not exceed the system solubility ceiling,and can also fall below the minimum continuous-delivery crop-qualityenhancer requirement.

Long-Felt Need

The present invention is believed to fulfill a long-standing andlong-felt need of the agricultural industry and is expected to garnergreat commercial success attributable to such fulfillment. Further, asseen from the above list of some basic crop-quality enhancers of thecrop-quality-enhancer feedstock, and their reactions, among thecrop-quality enhancers are strong acids, such as sulfuric, nitric andphosphoric acids, and these preferably will be used in the presentinvention in concentrated form. Also among the crop-quality enhancersare strong bases, such as potassium hydroxide and ammonium hydroxide(ammonia), and these preferably will be used in the present invention inconcentrated form. All of these crop-quality enhancers possess a largeheat of dissolution. Moreover, there is a large heat of reaction when anacid and a base react, which is a type of reaction that is among thereactions listed above. In addition, the MSDS safety sheets for acidswarn about the incompatibility with bases, and the MSDS safety sheetsfor bases warn about the incompatibility with acids, and therefore teachaway from the present invention.

The System of FIG. 1 to FIG. 3

Referring to FIG. 1 and, to the extent components are shown in FIG. 2and FIG. 3, to FIG. 2 and FIG. 3 also, there is shown a system of thepresent invention designated by the general reference numeral 10. Anagricultural irrigation system distributes irrigation water typicallyfrom a water source whether it be a well, surface water (such as waterin a canal, reservoir, stream or the like), reclaimed or recycled water.A stream of irrigation water is pumped into a main line (irrigationsystem main line) and then is filtered. The system 10, as shown in FIG.1, FIG. 2 and FIG. 3, is an embodiment of an extended system of thepresent invention because system 10 includes such filters and a segmentof such a main line from a point upstream of the filters to a pointdownstream of the filters, and the addition of crop-quality-enhancerfeedstock raw materials occurs between these two points.

As described below, a segment of a stream of irrigation water that isrunning between the irrigation-water source and the irrigation line(s)in the field(s) is within the system 10 wherein the irrigation water isfirst filtered and then treated by the addition of one or morecrop-quality enhancers, and as exemplified here, the in-situ manufactureof one or more fertilizers derived from feedstock of the presentinvention. The system 10 includes a control unit 12, optionally aplurality of filters, which here are shown as sand-media filters 16, anirrigation-water line, which here is shown as a pre-filter (and somewhathigher pressure) segment of an irrigation-water main line, or pre-filtermain line 18, which feeds irrigation water (identified and discussedbelow) through each of the sand-media filters 16, and also through amixing chamber 14, to a post-filter (and somewhat lower pressure)segment of the irrigation-water main line, or post-filter main line 20.(The post-filter main line 20 is a transport pipe that carriesirrigation water to one or more agricultural fields, such as theagricultural field 510 shown in phantom, and obviously not to scale, inFIG. 1. One or more secondary transport pipes service a typicalagricultural field, such as transport pipes 520 shown in FIG. 1. Devicesfor delivering the irrigation water at points in the field, shown asdevices 530 in FIG. 1, can be overhead sprinklers or micro-devices (suchas emitters or micro-sprinklers.) The feedstock raw materials are storedin separate storage containers which may be conveniently disposed nearbythe control unit 12 as shown. As shown, such storage containers includeone for each of eight crop-quality enhancers, namely a sulfuric acidtank 22, a calcium nitrate tank 24, a magnesium nitrate tank 26, anitric acid tank 28, a phosphoric acid tank 30, a urea tank 32, apotassium hydroxide tank 34 and an ammonium hydroxide tank 36. (Theseand/or other storage tanks can likewise hold any other crop-qualityenhancer, including but not limited to commercial fertilizers.) (Thestorage tanks 22, 24, 26, 28, 30, 32, 34, 36 are shown staggered forsimplicity in showing each of the crop-quality enhancer feed lines 40.)

As mentioned above, and as shown for system 10, eightcrop-quality-enhancer feed tanks, namely a feed tank for each and everycrop-quality enhancer of the system 10, are provided. The presentinvention, however, does not exclude the use of fewer than all eightcrop-quality enhancers because there are growers who need and/or desirefewer than all of the fertilizer nutrients that can be provided from thein-situ manufacture that occurs from the eight crop-quality enhancers ofcertain embodiments of the system of the present invention. The presentinvention in certain embodiments instead uses at least a plurality ofthe eight crop-quality enhancers (at least one of which contains atleast one of the NPK nutrients), and there typically is no practicalreason for having other than the same number of crop-quality-enhancerfeed tanks as the number of crop-quality enhancers used.

There is a crop-quality-enhancer feed line 40 between each of thecrop-quality-enhancer tanks and the mixing chamber 14. Thesecrop-quality-enhancer feed lines 40 run through the interior of thecontrol unit 12 (not shown in FIG. 1) to the mixing chamber 14. (Onlyone of such crop-quality-enhancer feed lines 40 is shown running to themixing chamber 14 for simplicity). For each of the crop-qualityenhancers, and crop-quality-enhancer feed lines 40, which for system 10is eight crop-quality enhancers and eight crop-quality-enhancer feedlines 40, there is an injection valve 96 along the crop-quality-enhancerfeed line 40 just ahead of the point at which the feed line 40 entersthe mixing chamber 14, none of which is shown in FIG. 1 for simplicity,and all eight of which are shown in FIG. 2 and FIG. 3.

Irrigation water flows to and through each of the sand-media filters 16through filter feed lines 72. A stream of the irrigation water alsoflows from the pre-filter main line 18 to the mixing chamber 14 througha mixing-chamber feed line 70, except when the mixing-chamber feed line70 is closed off. The water flows from the mixing chamber 14 and fromeach of the sand-media filters 16 discharge to the post-filter main line20.

Referring now in particular to FIG. 2 (where the storage tanks 22, 24,26, 28, 30, 32, 34, 36 are again shown staggered for simplicity inshowing each of the crop-quality enhancer feed lines 40), each of thecrop-quality-enhancer feed lines 40 is equipped with a feed pump 74.Each of these feed pumps 74 (except the feed pump 74 along thecrop-quality-enhancer feed line 40 from the sulfuric acid feed tank 22when sulfuric acid is being used solely for pH adjustment and not forinstance as a raw material for the manufacture of a fertilizer such asshown in Equations 2 through 4b above) is controlled by a flowcontroller 76 and a master controller 78. The feed pump 74 along thecrop-quality-enhancer feed line 40 from the sulfuric acid feed tank 22when sulfuric acid is being used solely for pH adjustment is controlledby the master controller 78 and a pH controller 80. Each of these feedpumps 74 (except the feed pump 74 along the sulfuric acid feed tank 22when sulfuric acid is being used solely to adjust pH) is in electricalcommunication with a flow controller 76 and the master controller 78(the electrical connections are not shown) and injects or pumps in itsrespective crop-quality enhancer to its respective feed line 40 at therate determined by the flow controller 76 and the master controller 78.The feed pump 74 along the sulfuric acid feed line 40 is generally inelectrical communication with the master controller 78 and the pHcontroller 80 (the electrical connections are not shown) and pumpssulfuric acid though its respective feed line 40 at the rate determinedby the flow controller 76, the master controller 78 and the pHcontroller 80.

The control unit 12 is divided into two chambers, one of which is alower chamber 82 which houses the feed pumps 74 and a portion of thecrop-quality enhancer feed lines 40 downstream of the respective tanks22, 24, 26, 28, 30, 32, 34, 36 and upstream of the mixing chamber 14.The lower chamber 82 also houses a pH monitoring system 83 (shown inphantom lines in FIG. 2) which, as shown, is comprised of a pHmonitoring-system pump 84, a pH sensor 86, a pH feed line 88 and a pHreturn line 90. The second chamber of the control unit 12 is an upperchamber 92 which houses the flow controller 76, the master controller78, the pH controller 80 and a temperature controller 77.

Along each of the crop-quality enhancer feed lines 40 downstream of therespective feed pumps 74 and upstream of the mixing chamber 14 is, asmentioned above, an injection valve 96, each of which is equipped with abackflow preventer (not shown). Along the mixing-chamber feed line 70are, in the order of from upstream (closest to the pre-filter main line18) to downstream (closest to the mixing chamber 14) an optional boosterpump 98, a mixing-chamber feed-line flow meter 100, a mixing-chamberfeed-line flow sensor 102 and a mixing-chamber feed-line shut-off valve104. The line opposite the mixing-chamber feed line 70 is amixing-chamber discharge line 71 that is open to the post-filter mainline 20. Along the mixing-chamber discharge line 71, in the order offrom upstream (closest to the mixing chamber 14) to downstream (closestto the post-filter main line 20), are a mixing-chamber discharge-linethermocouple 106 and a mixing-chamber discharge-line shut-off valve 108.

The pre-filter main line 18 is open to the mixing chamber 14 through themixing-chamber feed line 70, and is open to each of the sand-mediafilters 16 through filter feed lines 72 or openings. Untreatedirrigation water, that is, irrigation water that is not yet treated bythe system of the present invention, which is shown by flow arrows andis designated as untreated irrigation water 110 in FIG. 3, flows throughthe pre-filter main line 18 and discharges to the mixing chamber 14 andthe sand-media filters 16 through these respective lines.

As noted above, the mixing-chamber discharge line 71 is open to, anddischarges to, the post-filter main line 20, which is best seen in FIG.3. In addition, each of the sand-media filters 16 is open to, anddischarges to, the post-filter main line 20 via filter discharge lines114 or openings. The untreated irrigation water 110 of the pre-filtermain line 18 thus flows to the post-filter main line 20 and thereinreceives the discharge from the mixing-chamber discharge line 71,becoming irrigation water that carries or has been treated with thecrop-quality-enhancer feedstock of the present invention. Such treatedirrigation water is shown by flow arrows and is designated as treatedirrigation water 111 in FIG. 3 and elsewhere herein.

Along the post-filter main line 20, in the order of from upstream(closest to the mixing-chamber discharge line 71) to downstream(farthest from the mixing-chamber discharge line 71), are the terminalend 116 of the pH return line 90, the starting end 120 of the pH feedline 88 (along which is a pH line shut-off valve 122 and a solenoid124), a post-filter main-line pressure gauge 126 and a post-filtermain-line flow sensor 128.

Along the pre-filter main line 18, in the order of from upstream(closest to the mixing-chamber feed line 70) to downstream (farthestfrom the mixing-chamber feed line 70), are a pre-filter main-linepressure sensor 130 and a pre-filter main-line pressure gauge 132.

The storage containers, namely the sulfuric acid tank 22, calciumnitrate tank 24, magnesium nitrate tank 26, nitric acid tank 28,phosphoric acid tank 30, urea tank 32, potassium hydroxide tank 34 andammonium hydroxide tank 36, can vary in size depending on the size andnutrient needs of the irrigation site they serve. Typical storagecontainer sizes are between 300 and 6,500 gallons. The electricalconnections between the feed pumps 74 along the crop-quality-enhancerfeed lines 40 and the controlling flow controller 76 and mastercontroller 78 (flow controller 76, master controller 78 and pHcontroller 80 for the feed line 40 of the sulfuric acid tank 22) eachconsist separately of an on/off power control (not shown) and a feedbackloop (not shown) which controls the output of the respective feed pumps74, and the construction and operation of such electrical connectionsare well within the skill of an ordinary person skilled in the art. Theupper chamber 92 of the control unit 12, which houses the electricalcontrols, namely the flow controller 76, the temperature controller 77,the master controller 78 and the pH controller 80, is isolated from thelower chamber 82 (which houses the feed pumps 74 and the pH monitoringsystem 83) to avoid, or at least inhibit, corrosion of the electricalcomponents of the electrical controls. The control unit 12 generally ispreferably constructed of heavy gauge steel that is anodized to inhibitcorrosion. It preferably is secured with a high security lock system(not shown) and is preferably anchored to the ground with several sixfoot deep spikes (not shown) to prevent tampering and/or theft of theequipment held within the control unit 12.

The flow controller 76 within the control unit 12, which is one of thecontrols over the feed pumps 74, is also in electrical connection (notshown) with the post-filter main-line flow sensor 128 along thepost-filter main line 20. (Additionally, the pH controller 80, which isin electrical connection (not shown) with the flow controller 76, willoverride the flow controller 76 at times to control the feed pump 74along the feed line 40 of the sulfuric acid tank 22 to give the targetpH. (The construction and operation of these electrical connections arewell within the skill of an ordinary person skilled in the art.) Theflow controller 76 proportionately varies the input of the crop-qualityenhancers through the respective feed pumps 74 based on the flow rate ofthe treated irrigation water 111 which is read by the post-filtermain-line flow sensor 128 downstream of (beyond) the sand-media filters16.

The temperature controller 77 within the control unit 12 is inelectrical connection (not shown) with the mixing-chamber discharge-linethermocouple 106 along the mixing-chamber discharge-line 71. (Theconstruction and operation of these electrical connections are wellwithin the skill of an ordinary person skilled in the art.) Thecrop-quality enhancers from the various storage tanks (referencenumerals 22-36) are routed through the respective crop-quality enhancerfeed lines 40 and charged to the mixing chamber 14 as thecrop-quality-enhancer feedstock of the present invention. The componentsof the crop-quality-enhancer feedstock, when there are more than onecomponent, are exposed to, intermixed with and at times reacted witheach other and a stream of untreated irrigation water 110 being fed intothe mixing chamber 14 through the mixing-chamber feed line 70. Upon suchexposure, intermixing and any reaction, there is an exotherm from theheat of dissolution and the various crop-quality enhancers may alsoreact as described above, and these reactions can be exothermic. Theseexotherms are the reason the temperature of the crop-quality-enhancerfeedstock and irrigation water mixture is preferably monitored by themixing-chamber discharge-line thermocouple 106 as thecrop-quality-enhancer feedstock exits the mixing chamber 14. If thattemperature is undesirably high, for instance 40° C. or higher (higherthan 39° C.), the temperature controller 77 sends a feedback signal tothe master controller 78 and the master controller 78 shuts off the feedpumps 74 until a safe temperature is seen at the mixing-chamberdischarge-line thermocouple 106, and this off/on sequence is repeateduntil a safe temperature, as seen at the mixing-chamber discharge-linethermocouple 106, is maintained.

The pH controller 80 is electrically connected (not shown) to the pHmonitoring system 83. (The construction and operation of theseelectrical connections are well within the skill of an ordinary personskilled in the art.) The pH controller 80 in conjunction with the pHmonitoring system 83 controls the pH of the treated irrigation water 111as it leaves the system 10. The pH of the treated irrigation water 111is monitored by diverting a very small stream of treated irrigationwater 111 through the starting end 120 of the pH feed line 88 (see FIG.3) to the pH sensor 86 (see FIG. 2) whereat the pH of that small streamis determined. Based on the pH of the treated irrigation water 111 andbased on the fertilizer crop-quality enhancer composition being producedin the mixing chamber 14, the pH controller 80 adjusts (increases ordecreases) the feed of acid(s) and/or base(s) to achieve a constanttarget treated irrigation water pH. (Under the present invention, a baseis available for increasing the pH if needed to achieve a constanttarget pH, although in practice a pH increase would normally not berequired. Further discussion herein of pH adjustment presumes thatdecreasing the pH is the only adjustment required.) The target treatedirrigation water pH is typically a pH of about 6.5. The feed pump 74along the feed line 40 from the sulfuric acid tank 22 is at timesactivated only when the target pH cannot be maintained by adjustments tothe feed pumps 74 of nitric acid and/or the phosphoric acid tanks 28, 30because sulfuric acid has no nutrient value. If the target pH can beobtained by slight additional amounts of nitric and/or phosphoric acid(both of which contain an NPK nutrient and thus have nutrient values),then the use of nitric and/or phosphoric acid to adjust the pH ispreferable, although the use of sulfuric acid for pH adjustment isobviously not excluded and can at times be more practical. Typically thetarget pH, which generally is between 6.5 and 7, is lower than the pH ofthe untreated irrigation water, because untreated irrigation water isusually alkaline, and of course a base would be used for the pHadjustment if the target pH is higher than the pH of the untreatedirrigation water.

The master controller 78 automatically turns the system 10 on. Themaster controller 78 is electrically connected (not shown) both to thepre-filter main-line pressure sensor 130 and to the mixing-chamberfeed-line flow sensor 102. (The construction and operation of theseelectrical connections are well within the skill of an ordinary personskilled in the art.) When a minimum pressure (typically 15 psi) is seenat the pre-filter main-line pressure sensor 130 and a minimum flow ofwater (typically twenty gallons per minute) is seen at themixing-chamber feed-line flow sensor 102, the master controller 78actuates the feed pumps 74 and injection valves 96 and any othercomponent of the system 10 which facilitate the treatment of theuntreated irrigation water that are then in an inactive state. Upon suchactuation, crop-quality enhancers start feeding to, mixing in, andpossibly reacting in, the mixing chamber 14 (The master controller 78,pre-filter main-line pressure sensor 130 and mixing-chamber feed-lineflow sensor 102 are typically always in an active state.). The mastercontroller 78 will not allow such actuation unless both minimums aremet. Once the feed pumps 74 and injection valves 96 are actuated, themaster controller 78, for safety reasons and preferably, willautomatically shut down the feed pumps 74 and injection valves 96 wheneither of the values seen at the pre-filter main-line pressure sensor130 and the mixing-chamber feed-line flow sensor 102 falls below itsrespective minimum, and automatically restart the feed pumps 74 andinjection valves 96 when both of the values seen at the pre-filtermain-line pressure sensor 130 and the mixing-chamber feed-line flowsensor 102 meet or exceed its respective minimum. In other words, oncethe flow of untreated irrigation water 110 to the fields begins, itstarts flowing (a) through the pre-filter main line 18, (b) to andthrough the sand-media filters 16, (c) discharging to, and flowingthrough the post-filter main line 20, and (d) from there to theirrigation lines in the field(s) (not shown), the master controller 78will actuate the feed pumps 74 and injection valves 96 if the irrigationwater is at the normal or expected pressure, flow and flow rate. Notethat generally the flow of irrigation will occur as described aboveregardless of whether the master controller 78 has actuated the feedpumps 74 and injection valves 96 or has shut down the feed pumps 74 andinjection valves 96 after initial actuation because that flow sequenceand infrastructure are the conventional elements of the irrigationsystem.

One of the components of the system 10 that might not be in an activestate when irrigation water first starts to flow, and when the feedpumps 74 and injection valves 96 re-actuate, is the solenoid 124 whichallows the small stream of the treated irrigation water 111 to bediverted to the pH monitoring system 83 via the pH feed line 88. Themaster controller 78 will normally and preferably activate the solenoid124 when it actuates the feed pumps 74 and injection valves 96. Theelectrical connections between the solenoid 124 and the mastercontroller 78 are not shown.

Based on the crop-quality enhancer profile (which might be anutrient-application profile, which is the type and amount of nutrientsthat are required for a given time period of the given crop cycle), themaster controller 78 automatically determines and sets the correctsynchronizations of the feed pumps 74 to provide the needed feedstockraw materials while avoiding any conflicting interactions between itscomponents in the mixing chamber 14 or downstream therefrom.

As mentioned elsewhere herein, the master controller 78 controls thetemperature within the mixing chamber 14, preventing the temperaturefrom straying out of (normally exceeding) the desired range, by shuttingoff the feed pumps 74 until that temperature drops to, and can bemaintained within, the desired range.

When filter(s) are disposed within the path of the irrigation waterflowing through the system of the present invention (which is standardbut not universal for commercial irrigation systems), such as thesand-media filters 16 shown within the path of the irrigation waterbetween the pre-filter main line 18 and post-filter main line 20 (exceptthe small stream of irrigation water that is routed through the mixingchamber 14), there is normally a small but significant water-flowpressure drop across the filters, such as sand-media filters 16. A flowrate of at least 20 gallons per minute or more of untreated irrigationwater 110 through the mixing chamber 14 is preferred, and the optionalbooster pump 98 is preferably included to provide such flow rate if thepressure drop across the sand-media filters 16 would result in a lowerflow rate through the mixing chamber 14 or if a higher flow rate isrequired to maintain a mixing chamber temperature below 40 degrees C.

As noted elsewhere, disposed along the mixing-chamber feed line 70 arethe booster pump 98, the mixing-chamber feed-line flow meter 100, themixing-chamber feed-line flow sensor 102 and the mixing-chamberfeed-line shut-off valve 104. The mixing-chamber feed-line flow meter100 determines the actual flow rate of untreated irrigation water 110to, and therefore through, the mixing chamber 14. The mixing-chamberfeed-line flow sensor 102 determines if a flow of untreated irrigationwater 110 is occurring to, and therefore through, the mixing chamber 14.The flow of crop-quality enhancers to the mixing chamber 14 will not bepermitted unless a flow of untreated irrigation water 110 is occurringthrough the mixing chamber 14. There of course are electricalconnections (not shown) between the mixing-chamber feed-line flow meter100 and the master controller 78, and between the mixing-chamberfeed-line flow sensor 102 and the master controller 78.

The mixing-chamber feed-line shut-off valve 104 is not generally anactive element in the operation of the present system, but instead it isan optional, and typically manual, expedient. The mixing-chamberfeed-line shut-off valve 104 and the mixing-chamber discharge-lineshut-off valve 108 (which likewise is an optional, and typically manual,expedient) can be conveniently used together to isolate the mixingchamber 14 from the flows of irrigation water for maintenance or repairpurposes, if ever needed. When the mixing-chamber feed-line shut-offvalve 104 and the mixing-chamber discharge-line shut-off valve 108 areopen (or in embodiments when they are not present), the small stream ofuntreated irrigation water 110 flows through the mixing chamber 14whenever the irrigation water is flowing to the fields (not shown),regardless of whether or not any crop-quality enhancers are being fed tothe mixing chamber 14.

Along the mixing-chamber discharge line 71, downstream of the mixingchamber 14, are the mixing-chamber discharge-line thermocouple 106 whichsenses the temperature of the crop-quality-enhancer feedstock andirrigation water mixture as it exits the mixing chamber 14, and sendsthat data signal (temperature reading) to the master controller 78 forits processing and control of the temperature within the mixing chamber14 as discussed elsewhere herein. There of course are electricalconnections (not shown) between the mixing-chamber discharge-linethermocouple 106 and the master controller 78.

Along the post-filter main line 20, in the order of upstream todownstream in relation to the flow through the post-filter main-line 20,are the terminal end 116 of the pH return line 90, the starting end 120of the pH feed line 88, the post-filter main-line pressure gauge 126 andthe post-filter main-line flow sensor 128. The terminal end 116 of thepH return line 90 is the return line from the pH monitoring system 83through which the small stream of treated irrigation water 111 that isdiverted through the pH feed line 88 to the pH monitoring system 83 isreturned to the post-filter main line 20.

As mentioned elsewhere, the small stream of treated irrigation water 111is diverted from the post-filter main line 20 to the pH monitoringsystem 83 through the pH feed line 88 and is returned to the post-filtermain line 20 (preferably, as shown, upstream of its diversion point)through the pH return line 90. Along the starting end 120 of the pH feedline 88 is a pH feed-line shut-off valve 122. Along the terminal end 120of the pH return line 90 is a pH return-line shut-off valve 123. The pHfeed-line shut-off valve 122 and the pH return-line shut-off valve 123are not normally active elements of the system 10 but instead areoptional, and typically manual, expedients which can be convenientlyused together to isolate the pH monitoring system 83 from the flows ofirrigation water for maintenance or repair purposes, if ever needed,without discontinuing the irrigation water flow through the remainder ofthe system 10.

The small stream of treated irrigation water 111 that is diverted fromthe post-filter main line 20 at the starting end 120 of the pH feed line88 feeds into the pH monitoring system 83 through the pH feed line 88.(The starting end 120 of the pH feed line 88 as seen in FIG. 3 and thepH feed line 88 as seen in FIG. 2 are opposite ends of a single flowline.) The pH of that small stream is read by the pH sensor 86 of the pHmonitoring system 83. Electrical connections between the pH sensor 86and the pH monitoring system 83 exist but are not shown. The pHmonitoring-system pump 84 pumps the small stream through the pHmonitoring system 83, and the pH monitoring-system pump 84 is controlledby the master controller 78 (electrical connections between theseelements are not shown.)

To summarize, the pH monitoring system 83 includes the pHmonitoring-system pump 84 which pumps treated irrigation water 111 fromthe post-filter main line 20 through the pH feed line 88, past the pHsensor 86, and then back to the post-filter main line 20 through the pHreturn line 90. The electrical connections between the pH monitoringsystem 83 and the pH controller 80 are not shown.

The solenoid 124 shuts off treated irrigation water 111 flow from thepost-filter main line 20 through the starting end 120 of the pH feedline 88 when the water-flow pressure seen at the pre-filter main-linepressure sensor 130 and/or at the mixing-chamber feed-line flow sensor102 drop below predetermined threshold values. The solenoid 124 is inelectrical connection (not shown) with the master controller 78.

The dispositions and functions of the post-filter main-line pressuregauge 126, pre-filter main-line pressure gauge 130 and the post-filtermain-line flow sensor 128 are discussed elsewhere.

The sand-media filters 16 are typically large, for instance 300 gallon,stainless steel filters. Such type of filters is routinely used bygrowers to remove debris from untreated irrigation water before itenters the irrigation system in the fields. The sand-media filters 16 ofthe system 10 of the present invention generally and preferably would befilters that are already in place at the given irrigation-system site.As the untreated irrigation water 110 passes through the sand of thesand-media filters 16, the flow of the untreated irrigation water 110 isrestricted and that flow restriction causes a small but significantpressure drop across the sand-media filters 16. Such pressure drop istypically in the range of from 5 to 15 psi (but can be higher as debrisbuilds up in the filter), and is the reason that there is a pressuredifferential between the pre-filter main line 18 and the post-filtermain line 20. This pressure drop facilitates a large (fast) flow ofuntreated irrigation water 110 through the mixing chamber 14 that isneeded to temper or mitigate the temperature increase stemming from thepotential exotherms within the mixing chamber 14. (As mentionedelsewhere, if the temperature of the water flowing out the mixingchamber 14 is too high, the charging of crop-quality-enhancer feedstockto the mixing chamber 14 is halted.) The previously-described optionalbooster pump 98 is available to create and/or maintain the requisitewater flow through the mixing chamber 14, and it is a highly recommendedoption for irrigation systems that do not have a large enough pressuredrop across the filters 16 to provide the requisite cooling by theuntreated irrigation water 110 when the crop-quality-enhancer feedstockis charged to the mixing chamber 14.

In other words, the flow of untreated irrigation water 110 water throughthe mixing chamber 14 is large (fast) compared to the feed rate(injection rate) of the crop-quality enhancers into the mixing chamber14, and thereby quenches any exotherm(s) caused by the charging ofcrop-quality-enhancer feedstock to the mixing chamber 14. It isgenerally believed that reactions between components of thecrop-quality-enhancer feedstock (to form the various fertilizersdiscussed above) occur within the mixing chamber 14 prior to thedischarge into the post-filter main line 20.

The level of crop-quality-enhancer feedstock that can be charged to themixing chamber 14 depends on the size of the mixing chamber 14. For anygiven level, the mixing chamber 14 and the stream of water flowingthrough it must be sufficiently large to dampen and mitigate any of thepotential exotherms generated.

In contrast, the system shown in FIG. 4 and described below charges thecrop-quality-enhancer feedstock directly into the irrigation main line,and therefore it intrinsically has a sufficient water flow to dampen andmitigate exotherms generated regardless of the level ofcrop-quality-enhancer feedstock charged. (Any level ofcrop-quality-enhancer feedstock that might raise exotherm concerns wouldbe far to high for any reasonable purpose.)

Master controller 78 includes various electronic components that aredesigned to monitor various electrical signals from the sensing devices.Depending on what signals are input, the master controller 78 turns onthe various components of the system once the irrigation system is fullyoperational and in a mode to insure the proper feed of all thecrop-quality enhancers in the correct proportions, under controlledconditions, to safely manufacture the fertilizer crop-quality enhancerinside the irrigation system. Numerous configurations of electriccomponents could be designed to achieve this control. As shown, themaster controller 78 consists of various relays, timing devices andpower supplies that take the various signals from the sensing equipmentand turn on and off the various control systems to safely control thechemical feed pumps 74 used to manufacture the various fertilizercrop-quality enhancers. (A master controller could of course send thesensing and control data, via wireless communication networks, to anoperator stationed in a distant office.) If any incorrect orout-of-range signal is received by the master controller 78 thecircuitry inside the master controller 78 responds and sends theappropriate feedback signal to the appropriate device or system toimmediately correct the out-of-range condition, change the flow rate ofone or more of the crop-quality enhancer feed pumps 74 or totally shutoff one or more of the crop-quality enhancer feed pumps 74.

The System of FIG. 4

Referring to FIG. 4, there is shown a segment of a system of the presentinvention designated by the general reference numeral 310, which differsfrom the system 10 of FIG. 1 to FIG. 3 by the omission of a separatemixing chamber component such as the mixing chamber 14 of the embodimentshown in FIG. 1 to FIG. 3. In the system 310 of FIG. 4, the crop-qualityenhancer feed lines 340 feed directly into a main line (as shown, intothe main line segment that is the post-filter main line 320.

The system 310 includes a control unit 312 (partially shown in FIG. 4),a plurality of filters 316, an irrigation-water line or main line (whichis designated in two segments, namely a pre-filter main line 318 and apost-filter main line 320) and filters 316 along the main line betweenits pre-filter segment (pre-filter main line 318) and its post-filtersegment (post-filter main line 320). Components of system 310 that arenot shown in FIG. 4 include the components within the control unit 312,namely a lower chamber which houses a feed-line feed pump, pHmonitoring-system pump, a pH sensor, a pH feed line and a pH returnline, and also an upper chamber which houses a flow controller, a mastercontroller, a pH controller and a temperature controller. Othercomponents of system 310 that are not shown in FIG. 4 include aplurality of storage containers (one for each of the two crop-qualityenhancers, namely a sulfuric acid tank and a potassium hydroxide tank,although this system 310 could just as well have eight storagecontainers to hold all eight crop-quality enhancers as shown for system10 of FIG. 1 through FIG. 3). In each instance the components of system310 that are not shown in FIG. 4, and their electrical connections, areanalogous to those described above for the system 10 shown in FIG. 1 toFIG. 3, and therefore no further description is needed here. Further,the components of system 310 that are shown in FIG. 4, and theirelectrical connections, also are analogous to those described above forthe system 10 shown in FIG. 1 to FIG. 3, except as explicitly statedotherwise herein, and therefore little or no further description isneeded here.

As mentioned above, there is a crop-quality-enhancer feed line 340between each of the two crop-quality-enhancer tanks (not shown) and thepost-filter main line 320. These crop-quality-enhancer feed lines 340run through the interior of the control unit 312 and, as seen in FIG. 4,from there to the post-filter main line 320. For each of thecrop-quality enhancers, and crop-quality-enhancer feed lines 340, whichfor system 310 is two crop-quality enhancers and twocrop-quality-enhancer feed lines 340, there is an injection valve 396along the crop-quality-enhancer feed line 340 just ahead of the point atwhich the feed line 340 enters, or discharges to, the post-filter mainline 320.

Irrigation water flows to and through each of the filters 316 throughfilter feed lines 372, and discharges from each of the filters 316 tothe post-filter main line 320. The crop-quality enhancers also dischargeto the post-filter main line 320 (via the feed lines 340) and along eachof the crop-quality enhancer feed lines 340 upstream of the post-filtermain line 320 is, as mentioned above, an injection valve 396, each ofwhich is equipped with a backflow preventer (not shown).

In system 310, unlike the system 10 shown in FIG. 1 to FIG. 3, not onlyis there no separate mixing chamber component, there is nomixing-chamber feed line, no optional booster pump, no mixing-chamberfeed-line flow meter, no mixing-chamber feed-line flow sensor, nomixing-chamber feed-line shut-off valve, no mixing-chamber dischargeline and no mixing chamber discharge-line shut-off valve. There is acomponent that is the functional equivalent of the mixing-chamberdischarge-line thermocouple 106, and that is a post-filter main-linethermocouple 406 that is positioned along the post-filter main line 320downstream of the points at which the feed lines 340 discharge to thepost-filter main line 320. The post-filter main-line thermocouple 406(“thermocouple 406”), like the mixing-chamber discharge-linethermocouple 106 of system 10, tracks the reaction and dissolutionexotherms by monitoring the irrigation-water temperature in the waterstream in which dissolution and reaction occurs.

The pre-filter segment of the main line (pre-filter main line 318) isopen to each of the filters 316 through filter feed lines 372 oropenings. Untreated irrigation water, that is, irrigation water that isnot yet treated by the system of the present invention, which is shownby flow arrows and is designated as untreated irrigation water 410 inFIG. 4, flows through the pre-filter main line 318 and discharges to thefilters 316 through the respective filter feed lines 372. In addition,each of the filters 316 is open to, and discharges to, the post-filtermain line 320 via filter discharge lines 314 or openings. The untreatedirrigation water 410 thus flows through the filters 316 and thereafterreceives the charge of crop-quality enhancers from their feed lines 340,becoming treated irrigation water that carries or has been treated withthe crop-quality enhancers of the present invention. Although chargingthe feedstock along a post-filter section of the main line (post-filtermain line 320) is preferred, charging the feedstock along a pre-filtersection of the main line (pre-filter main line 318) is not excluded fromthe present invention. The feedstock charge should, however, bepre-delivery (upstream of the point(s) of delivering the irrigationwater to the crop). Such irrigation water is shown by flow arrows and isdesignated as treated irrigation water 411 in FIG. 4 and elsewhereherein.

Along the post-filter main line 320, in the order of from upstream(where the stream of irrigation water has not flowed past the feed lines340 and therefore the water is filtered but not yet irrigation water409) to downstream (farthest along the post-filter main line 320), arethe terminal end 416 of the pH return line, the crop-quality enhancerfeed lines 340, the thermocouple 406 (mentioned above), the starting end420 of the pH feed line (along which is a pH line shut-off valve 422 anda solenoid 424), a post-filter main-line pressure gauge 426 and apost-filter main-line flow sensor 428.

Along the pre-filter main line 318, in the order of from upstream(closest to the water source, not shown) to downstream, are a pre-filtermain-line pressure sensor 430 and a pre-filter main-line pressure gauge432.

The temperature controller (not shown) within the control unit 312 is inelectrical connection (not shown) with the thermocouple 406 along thepost-filter main line 320. (The construction and operation of theseelectrical connections are well within the skill of an ordinary personskilled in the art.) The crop-quality enhancers from the various storagetanks (not shown) are routed through the respective crop-qualityenhancer feed lines 340 and charged to the post-filter main line 320 asthe crop-quality-enhancer feedstock of the present invention. Thecomponents of the crop-quality-enhancer feedstock are exposed to andintermix with each other and the relatively large stream of filteredirrigation water 409 flowing out from the filters 316, and react witheach other. Upon such exposure, intermixing and possible reaction, theremay be an exotherm from the heat(s) of dissolution and exothermicreactions between the various crop-quality enhancers. These exothermsare the reason the temperature of the crop-quality-enhancer feedstockand irrigation water mixture is preferably monitored by the thermocouple406 downstream of the points at which the feed lines 340 discharge thecrop-quality enhancers to the post-filter main line 320. If thattemperature is undesirably high, for instance 40° C. or higher (higherthan 39° C.), the temperature controller (not shown) sends a feedbacksignal to the master controller (not shown) and the master controllershuts off the feed pumps (not shown) until a safe temperature is seen atthe thermocouple 406, and this off/on sequence is repeated until a safetemperature, as seen at the thermocouple 406, is maintained. The volumeand flow of irrigation water 409 in the post-filter main line 320 are,however, far greater than that through the mixing chamber 14 of system10 shown in FIG. 1 to FIG. 3, and therefore the likelihood of anexcessively high temperature being seen at the thermocouple 406approaches negligible, regardless of the concentration of crop-qualityenhancers which are being fed, outside of, of course, a major water-flowproblem in the irrigation system itself.

The starting end 420 of the pH feed line is downstream of the point(s)at which the crop-quality enhancers are charged to the post-filter mainline 320 and therefore, as in system 10 shown in FIG. 1 to FIG. 3, it isthe pH of the treated irrigation water 411, not the irrigation waterprior to treatment, which is being monitored by diverting a very smallstream of treated irrigation water 411 through the starting end 420 ofthe pH feed line to the pH sensor (not shown) whereby the pH controller(not shown) adjusts (increases or decreases) the feed of acid(s) and/orbase(s) to achieve a constant target treated irrigation water pH. Thetarget treated irrigation water pH is typically a pH of about 6.5. Sincethe crop-quality enhancers being charged in system 310 are sulfuric acidand potassium hydroxide, which at least to a degree react to formpotassium sulfate or potassium hydrogen sulfate depending upon therelative amounts being charged, as shown in Equations 2 and 3 aboverespectively, a pH adjustment via an adjustment in the sulfuric acidfeed is particularly practical here, and this approach exemplifies aninstance when sulfuric acid, which itself does not contain an NPKnutrient, might be charged simultaneously as a crop-quality enhancerthat is a raw material for manufacturing a fertilizer and as acrop-quality enhancer that is a pH adjustment additive.

The master controller (not shown) automatically turns the system 310 on.The master controller is electrically connected (not shown) to thepre-filter main-line pressure sensor 430. (The construction andoperation of these electrical connections are well within the skill ofan ordinary person skilled in the art.) When a minimum pressure(typically 15 psi) is seen at the pre-filter main-line pressure sensor430, the master controller actuates the feed pumps (not shown) andinjection valves 396 and any other component of the system 310 whichfacilitate the treatment of the irrigation water that are then in aninactive state. Upon such actuation, crop-quality enhancers startfeeding to the post-filter main line 320 as the crop-quality-enhancerfeedstock of the present invention. The master controller will not allowsuch actuation unless the minimum is met. Once the feed pumps (notshown) and injection valves 396 are actuated, the master controller, forsafety reasons and preferably, will automatically shut down the feedpumps and injection valves 396 when the value seen at the pre-filtermain-line pressure sensor 430 falls below its minimum, and automaticallyrestart the feed pumps and injection valves 396 when the value seen atthe pre-filter main-line pressure sensor 430 meets or exceeds itsrespective minimum. In other words, once the flow of untreatedirrigation water 410 to the fields begins, the irrigation water startsflowing (a) through the pre-filter main line 318, (b) to and through thefilters 316, (c) discharging to, and flowing through the post-filtermain line 320, and (d) from there to the irrigation lines in thefield(s) (not shown), and when this flow starts, the master controllerwill actuate the feed pumps and injection valves 396 provided thisirrigation water flow is at the normal, or expected, pressure, flow andflow rate. Note that generally the flow of irrigation will occur asdescribed above regardless of whether the master controller has actuatedthe feed pumps and injection valves 396 or has shut down the feed pumpsand injection valves 396 after initial actuation because that water flowsequence and infrastructure are the conventional elements of theirrigation system.

Again, the remainder of the system 310 is analogous to the system 10shown in FIG. 1 to FIG. 3 and described in detail above. Further, asdescribed above for system 310, the “mixing chamber” concept is part of,or within, the irrigation main line, namely the post-filter section ofthe irrigation main line (post-filter main line 320). The dilution ofthe crop-quality-enhancer feedstock in this far greater water stream isof course highly increased, thereby minimizing the exotherms even morethan is possible with a separate mixing chamber component such as themixing chamber 14 of system 10. Further, system 310 is simpler thansystem 10 because most of the controls associated with a separate mixingchamber component such as the mixing chamber 14 of system 10 areeliminated, as described above, and even the thermocouple 406 may be anunnecessary safety component because the level of crop-quality-enhancerfeedstock being charged is so extremely low in comparison to the volumeof irrigation water to which it is being charged.

Example 1 and Comparative Example A Projections

The method of the present invention in comparison to conventionalfertilization practices was evaluated for use at a very large vineyard.The grower conducted plant tissue analyses and soil analyses todetermine the fertilization requirements. Based on these analyses, thefertilization recommendations to the grower for a single crop cycle areshown in Table 2 below:

TABLE 2 Recommended Recommended Nutrient Amount Nitrogen 50 lb/acre as NPhosphorus 22 lb/acre as P2O5 Potassium 40 lb/acre as K2O Calcium 39lb/acre as Ca Magnesium  6 lb/acre as Mg

Although these are the nutrients that meet the grower's agronomic needs,they clash in several ways with conditions on this ranch whenconventional fertigation practices are considered. (1) The list ofrecommended nutrients includes phosphorus which is derived fromphosphate fertilizers. This grower has experienced severe pluggingproblems in the past when feeding any type of conventional phosphatefertilizer, and therefore phosphate is never added through this grower'smicro-irrigation system and instead it is manually field spread at thisvineyard. (2) The list of recommended nutrients also includes calciumwhich is commonly derived from gypsum, but this grower has alsoexperienced severe plugging problems in the past when feeding gypsum.The only alternative conventional commercial calcium source is CAN-17which a mixture of calcium and ammonium nitrates which this grower canuse if it is fed and then the irrigation system is, without delay,treated with concentrated sulfuric acid to remediate the pluggingresulting from the interaction of the hard and alkaline irrigation waterwith the high concentration of calcium arising from slug feeding CAN-17.This remedial treatment, which is done to remedy the plugging due to theformation of calcium carbonate precipitates inside the irrigationsystem, requires the grower to have a service inject sulfuric acid to alevel that reduces the pH of the irrigation water to approximately a pHof 4.0 throughout an irrigation time period of four to six hours.Extreme care must be taken during this remedial treatment because such alow pH could damage metal components and/or embrittle plastic componentsof the irrigation system. This conventional-practice alternativerequires the additional cost and handling of a very dangerous material,namely concentrated sulfuric acid, and the amount of CAN-17 (thecommercial mixture of calcium and ammonium nitrates) required to providethe recommended 39 pounds per acre of calcium will concomitantly provide75 pounds per acre nitrogen (as N), which is fifty percent greater thanthe recommended nitrogen. (3) The list of recommended nutrients alsoincludes magnesium which this grower can add through the irrigationsystem in a manner similar to the addition of calcium. Such addition ofmagnesium, however, also requires a subsequent flushing of theirrigation system with concentrated sulfuric acid for the same type ofreasons and with the same type of downsides as noted above for thealternative calcium source.

Comparative Example A Details

This grower can use a combination of conventional fertigation andmechanical fertilization practices which gives the grower the ability toadd all of the required fertilizer nutrients, but only with considerabledownsides. The most practical, agronomical approach requires the use(and storage and handling) of five different solutions. (1) A commercialcalcium nitrate-ammonium nitrate solution (CAN-17, discussed above) isselected as the calcium (and nitrogen) source because it is a standard,large scale, commercially available fertilizer solution. As mentionedabove, the amount of nitrogen that will be applied when using CAN-17 tomeet the calcium recommendation is significantly (fifty percent) inexcess of the recommendation and necessitates the slug feeding of thisfertilizer to the irrigation system in two approximately equalapplications, namely one at the beginning of the crop cycle and a secondin the middle of the crop cycle. (2) A magnesium nitrate solution isused as the magnesium source. At the recommended 6 lbs./acre magnesium(Mg) this fertilizer also adds 7 lbs./acre nitrogen (N) which furtherincreases the nitrogen excess. In addition, there are no readilyavailable, large scale sources of this fertilizer solution, and it mustbe specially made for this grower. This fertilizer would be slug fed tothe irrigation system in one application shortly after the beginning ofthe crop cycle. (3) Concentrated sulfuric acid source would be slug fedwithout delay after each slug feeding of the calcium source andmagnesium source to eliminate or minimize the plugging of the irrigationsystem with insoluble calcium and magnesium carbonates formed duringtheir additions. Since concentrated sulfuric acid is an extremelyhazardous material for any grower to handle, it is not a desirablematerial to store and use on this vineyard although it must be storedand used in this “agronomic best-choice” Comparative Example A. (4) Apotassium nitrate solution is used as the potassium source. At 40lbs./acre as potash (K2O) this fertilizer also adds 12 lbs./acrenitrogen (N) which again increases the nitrogen excess. This fertilizerwould be slug fed to the irrigation system in three equal applicationsat the beginning, middle and end of the crop cycle. (5) Phosphoric acidis used as the phosphorus source. Due to the history of severephosphate-produced plugging experienced by this grower, which presumablyhas arisen from an incompatibility between phosphates and the irrigationwater, this phosphorus source is field spread by the grower in theamount of 22 lbs./acre of phosphate, as phosphorus pentoxide (P2O5), intwo equal applications, namely one at the beginning and another towardthe end of the crop cycle. (Phosphoric acid is the material of choicebecause no additional nitrogen is required or desired.) In Table 3 belowthere is shown the actual nutrient levels being added, in comparison tothe recommended levels, and the number of slug feedings and mechanicalspreadings required to meet the nutrient recommendations usingconventional fertigation and fertilization methods.

TABLE 3 Number of Nutrient Recom- Number of Required (basis for mendedActual Slug Mechanical amounts) Amount Amount Feedings SpreadingsNitrogen 50 94 (concomitant — (lb/acre with as N) potassium, calcium &magnesium additions) Phosphorus 22 22 — 2 (lb/acre as P2O5) Potassium 4040 3 — (lb/acre as K2O) Calcium 39 39 2 — (lb/acre as Ca) Magnesium 6 61 — (lb/acre as Mg) Conc. Sulfuric — as needed 3 — acid for (after eachcleaning calcium after each & calcium & magnesium magnesium addition)addition

As seen in Table 3 above, not only are six separate slug feedings, three“cleaning” slug feedings and two mechanical spreadings required, this“agronomic best choice” Comparative Example A results in the addition ofnitrogen at a level almost twice as high as the recommended amount.

Comparative Example A Irrigation Water Profiles

Irrigation water usage of (a) 1.0 ac-ft/acre during the time period fromFebruary 1 through June 30; and (b) 1.0 ac-ft/acre during the timeperiod from July 1 through September 30. Irrigation water flow rate of1,000 gal./min. Irrigation water pH of 8.0 except during the three daysof cleaning with concentrated sulfuric acid. Irrigation duration (as toslug feeding time) of six hours per slug-feed day. As noted above, theacreage being irrigated is 150 acres.

Comparative Example A Slug-Feeding Projections and Multivalent IonLevels

The slug-feeding dates, the fertilizer/additive slug-fed and the amountand type of nutrient/additive applied are set forth in Table 3.1 below.

TABLE 3.1 Fertilizer/ Amount(s) of Nutrient/ Date Additive AdditiveApplied 2/1 CAN-17 37.7 lbs/acre N (as N) and 2/2 Sulfuric Acid (conc.)19.5 lbs/acre Ca (as Ca) as required as cleaner 2/8 Magnesium nitratesoln. 6.9 lbs/acre N (as N) and 2/9 Sulfuric Acid (conc.) 6.0 lbs/acreMg (as Mg) as required as cleaner 2/15 Phosphoric Acid (conc.) 11.0lbs/acre P (as P2O5) 3/1 Potassium nitrate 15.0 lbs/acre K (as K2O) and4.5 lbs/acre NO-3 (as N) 6/15 Potassium nitrate 10.0 lbs/acre K (as K2O)and 3.0 lbs/acre NO-3 (as N) 7/1 CAN-17 37.7 lbs/acre N (as N) and 19.5lbs/acre Ca (as Ca) 7/2 Sulfuric Acid (conc.) as required as cleaner9/15 Potassium nitrate 15.0 lbs/acre K (as K2O) and 4.5 lbs/acre NO-3(as N) 9/30 Phosphoric Acid (conc.) 11.0 lbs/acre P (as P2O5)As discussed above, multivalent cations and anions are the primary causeof precipitation. The slug feeding of 19.5 lbs/acre calcium (as Ca) overthe six-hour irrigation period at the 1,000 gal./min. flow rate on 2/1and 7/1 generates a 977 ppm level of Ca+2 in the irrigation water. Theslug feeding of 6.0 lbs/acre magnesium (as Mg) over the six-hourirrigation period at the 1,000 gal./min. flow rate on 2/8 generates a301 ppm level of Mg+2 in the irrigation water. The 11.0 lbs/acrephosphorus (as P2O5) cannot be slug fed into the irrigation system andmust be field spread. The result stems from the fact that high levels ofphosphate added to hard and alkaline irrigation water are not compatibleand form an insoluble precipitate. This insoluble calcium phosphateprecipitate caused the disastrous plugging of the irrigation system thatthe grower has experienced in the past and is why the grower was forcedto field spread the phosphorus. Nevertheless, for comparative purposesif the phosphoric acid could be added to the irrigation system the slugfeeding of 11.0 lbs/acre phosphorus (as P2O5) over the six-hourirrigation period at the 1,000 gal./min. flow rate on 2/15 and 9/30generates a 551 ppm level of P2O5, which is a 738 ppm level of PO4-3 inthe irrigation water. All of these levels of multivalent cations andanions are well in excess of the levels that, in combination with thehardness and alkalinity already present in the irrigation water, causeprecipitation and subsequent plugging of the irrigation system.

Example 1 Irrigation Water Profiles

Irrigation water usage of (a) 1.0 ac-ft/acre during the time period fromFebruary 1 through June 30; and (b) 1.0 ac-ft/acre during the timeperiod from July 1 through September 30. Irrigation water flow rate of1,000 gal./min. Irrigation water pH of 6.5. Irrigation duration (as tocontinuous feeding time) of six hours per irrigation period. As notedabove, the acreage being irrigated is 150 acres.

Example 1 Continuous-Feeding Projections and Multivalent Ion Levels

The continuous manufacture and addition time periods, the crop-qualityenhancers continuously fed and the amount and type of nutrient/additiveapplied are set forth in Table 4 below.

TABLE 4 Time Raw Amount(s) of Nutrient/ period Materials AdditiveApplied 2/1-6/30 Calcium nitrate 13.7 lbs/acre nitrate nitrogen soln.(as N) and 19.5 lbs/acre Ca (as Ca) same Magnesium 6.9 lbs/acre nitratenitrogen nitrate soln. (as N) and 6.0 lbs/acre Mg (as Mg) same Ureasoln. 7.0 lbs/acre urea nitrogen (as N) same Ammonium 8.7 lbs/acreammoniacal nitrogen hydroxide soln. (as N) same Potassium 25.0 lbs/acrepotassium (as K2O) hydroxide soln. same Phosphoric 11.0 lbs/acrephosphorus acid (conc.) (as P2O5) same Sulfuric acid as required to bothreact with other (conc.) crop-quality enhancers and lower theirrigation-water pH to 6.5 7/1-9-30 Calcium nitrate 13.7 lbs/acrenitrate nitrogen soln. (as N) and 19.5 lbs/acre Ca (as Ca) samePotassium 15.0 lbs/acre potassium (as K2O) hydroxide soln. samePhosphoric 11.0 lbs/acre phosphorus acid (conc.) (as P2O5) same Sulfuricacid as required to both react with other (conc.) crop-quality enhancersand lower the irrigation-water pH to 6.5Again, as discussed above, multivalent cations and anions are theprimary cause of precipitation. The continuous feeding of 19.5 lbs/acrecalcium (as Ca) first over a five-month time period (2/1-6/30) and thenover a three-month time period (7/1-9/30) in six-hour irrigation periodsat the 1,000 gal./min. flow rate generates at most a 7.2 ppm level ofCa+2 in the irrigation water. The continuous feeding of 6.0 lbs/acremagnesium (as Mg) over a five-month time period (2/1-6/30) in six-hourirrigation periods at the 1,000 gal./min. flow rate generates a 2.2 ppmlevel of Mg+2 in the irrigation water. The continuous feeding of 11.0lbs/acre phosphorus (as P2O5) over a five-month time period (2/1-6/30),or the continuous feeding of 11.0 lbs/acre phosphorus (as P2O5) over athree-month time period (7/1-9/30), in six-hour irrigation periods atthe 1,000 gal./min. flow rates generates at most an 4.1 ppm level ofP2O5, which is a 5.4 ppm level of PO4-3 in the irrigation water. All ofthese levels of multivalent cations and anions are below the levelsthat, in combination with the hardness and alkalinity already present inthe irrigation water, cause precipitation and subsequent plugging of theirrigation system. In comparison to Comparative Example A, there is a136 fold reduction of Ca+2 concentration in the irrigation water, a 137fold reduction of Mg+2 concentration in the irrigation water and a 137fold reduction of PO4-3 concentration in the irrigation water. Thesereductions were achieved while providing nitrate nitrogen(fast-release), urea nitrogen (controlled release) and ammoniacalnitrogen (slow release) in roughly equal amounts. In addition, thesereductions were achieved without delivering any excess nitrogen to thecrop. Further, the method of the present invention allows phosphate tobe successfully added to the irrigation system without disastrousplugging and eliminates the need for field spreading phosphate.

Example 2 and Comparative Example B Projections

The method of the present invention in comparison to conventionalfertilization practices was evaluated for use at a 150 acre almond ranchthat has been using conventional fertilization practices for years. Forthis comparison, a fertigation program similar to that used in the pastwas selected for the projection of Comparative Example B. The projectionof Example 2 is based on the same nutrients as Comparative Example B atamounts that are approximately 25 percent lower because, as discussedabove, a far higher percentage of the nutrients applied are available tothe crop in comparison to conventional fertilization practices such asthose of Comparative Example B. These projections are shown in Table 5below.

TABLE 5 Comparative Example B Example 2 Recommended RecommendedRecommended Nutrient Amount Amount Nitrogen (as N) 200 lb/acre as N 150lb/acre as N Phosphorus (as P2O5)  70 lb/acre as P2O5  50 lb/acre asP2O5 Potassium (as K2O) 175 lb/acre as K2O 125 lb/acre as K2O Calcium(as Ca)  35 lb/acre as Ca  25 lb/acre as Ca Magnesium (as Mg)  0 lb/acreas Mg  4 lb/acre as Mg

The agricultural area of this Example 2 and Comparative Example B,namely the 150 acre almond ranch, will normally receive a total of fouracre-feet of irrigation water over its eight-month (March 1 toNovember 1) growing season, delivered as follows: (a) 1.0 acre-footduring the first three months (March 1 through June 1); 2.5 acre-feetduring the second three months (June 1 through September 1); and 0.5acre-foot during the last two months (September 1 through November 1).An acre-foot is 325,851 gallons, and therefore 195.5 million gallons ofirrigation water are delivered to the acreage of this ranch per growingseason. The conventional fertigation program or schedule historicallyrequired on this almond ranch to meet the nutrient profile (shown againin Table 6 below) is shown in Table 7 below. The fertigation programrequired using the method of the present invention to meet the adjustednutrient profile (shown again in Table 8 below) is shown in Table 9below. The downward adjustment of the nutrient profile for the method ofthe present invention is a very conservative estimate of the lowernutrient levels required when nutrients are no longer being lost to theroot area as described above for conventional fertilization.

TABLE 6 Nutrient Profile Nutrient Total Nutrient Amount Nitrogen (as N)200 lb/acre Phosphorus (as P2O5)  70 lb/acre Potassium (as K2O) 175lb/acre Calcium (as Ca)  35 lb/acre Magnesium (as Mg)  0 lb/acre

TABLE 7 Conventional Fertigation Schedule Amounts Slug Fed (lb./acre)Mar. 1 Mar. 15 Mar. 30 May 15 Jul. 1 Sep. 15 Sep. 30 Fertilizer Solution(% N-P-K & other nutrients) CAN-17 (17-0-0 + 8.8 Ca) 198.9 198.9NH4H2PO4 (10-34-0) 102.9 102.9 UAN-32 (32-0-0) 349.4 K2S2O3 (0-0-25) 400300 Nutrient by Type Nitrate nitrogen (as N) 23.07 27.08 23.07Ammoniacal nitrogen (as N) 10.74 10.29 27.08 10.74 10.29 Urea nitrogen(as N) 57.65 Phosphorus (as P2O5) 35.0 35.0 Potassium (as K2O) 100 75Calcium (as Ca) 17.5 17.5

TABLE 8 Adjusted Nutrient Profile Nutrient Total Nutrient AmountNitrogen (as N) 150 lb/acre Phosphorus (as P2O5)  50 lb/acre Potassium(as K2O) 125 lb/acre Calcium (as Ca)  25 lb/acre Magnesium (as Mg)  4lb/acre

TABLE 9 Continuous-Feed On-Site Manufacture Fertilization Schedule TotalAmounts Fed Over Time Periods (lb.) Mar. Apr. May Jun. Jul. Aug. Sep.Oct. Fertilizer Solution (% N-P-K & other nutrients) Calcium nitrate ←70.59 → ← 70.59 → ← 70.59 → (8.3-0-0 + 11.8 Ca) Magnesium nitrate ←21.11 → ← 21.11 → ← 21.11 → (7.2-0-0 + 6.3 Mg) Nitric acid ← 116.7 → ←33.91 → ← 33.91 → (15.1-0-0) Ammonium ← 104.2 → ← 52.8 → ← 52.8 →hydroxide (24-0-0) Urea (23-0-0) ← 108.7 → ← 54.36 → ← 54.35 →Phosphoric acid ← 55.24 → ← 36.83 → (0-54.3-0) Potassium ← 119.00 → ←59.5 → ← 119.0 → hydroxide (0-0-42) Nutrient (by type) Nitrate nitrogen← 25.00 → ← 12.50 → ← 12.50 → (as N) Ammoniacal ← 25.00 → ← 12.50 → ←12.50 → nitrogen (as N) Urea nitrogen ← 25.00 → ← 12.50 → ← 12.50 → (asN) Phosphorus ← 30.00 → ← 20.00 → (as P2O5) Potassium ← 50.00 → ← 25.00→ ← 50.00 → (as K2O) Calcium (as Ca) ← 8.33 → ← 8.33 → ← 8.33 →Magnesium ← 1.33 → ← 1.33 → ← 1.33 → (as Mg)

Comparative Example B and Example 2 Projection Comparisons Slug FeedComparative Example B Projection (Nitrate Nitrogen)

On March 1 nitrate nitrogen (as N) is slug fed into the irrigationsystem. Specifically, 23.07 lbs./acre nitrate (as N) from a CAN-17source is fed to 150 acres at a flow rate of 1200 gallons/min. for thisgrower's normal 9.0 hour irrigation period. (CAN is an acronym for anaqueous solution of calcium nitrate and ammonium nitrate.) The nitratenitrogen (as N) concentration in the irrigation water during this slugfertigation process is: (23.07 lbs./acre NO3- (as N)×150 acres×1000grams/2.2 lbs.)/(1200 gal./min.×9 hrs.×60 min./hr.×3.78 liters/gal.×1000ml/l liter) or 642 ppm NO3- (as N).

The amount of water used during this slug fertigation process is, usingthe parameter that an ac-ft (acre-foot) is 325,851 gallons of water:1200 gal./min.×60 min./hr.×9 hrs.=648,000 gal.×1 ac-ft/325,851 gal. or1.99 ac-ft.

The 1.99 ac-ft of water is distributed over 150 acres and therefore theper-acre water distribution (1.99 ac-ft/150 acres) is 0.0133 ac-ft/acre.The next slug feed fertigation is May 15. The total evenly-distributedirrigation water to be delivered during March, April and May is 1 ac-ft.Therefore the amount of irrigation water delivered during the period ofMarch 2nd (the day after the March 1st slug feeding) and May 14 (the daybefore the May 15th slug feeding) is about “1 ac-ft/acre×(2.5 months/3.0months)” or 0.833 ac-ft/acre, and it will contain no nitrate nitrogenfertilizer. Again, this grower's normal irrigation period is 9 hours.Therefore after the single slug feed of fertilizer there are about“[(0.833 ac-ft/acre)/(0.0133 ac-ft/acre)−1]” or 61.6 irrigation periodson which no nitrate nitrogen fertilizer is delivered with the irrigationwater.

Continuous Feed—Example 2 Projection (Nitrate Nitrogen):

A total of 25.00 lbs./acre nitrate nitrogen is continuously charged tothe irrigation water distributed during each irrigation period duringthe months of March, April and May (from March 1 up to, but notincluding, June 1). For purposes of comparison to the slug-fedprojection above, only the nitrate nitrogen charged, and the irrigationwater delivered, during the shorter period of between March 1 and May 15is considered. The comparative (normalized) amount of nitrate nitrogenis therefore 20.83 lbs./acre nitrate. The nitrate nitrogen (as N)concentration in the irrigation water during this continuous fertigationprocess is: (20.83 lbs./acre×150 acres×1000 grams/2.2 lbs.)/(0.833ac-ft/acre×325,851 gal./ac-ft×3780 ml/gal.×150 acres) or 9.2 ppm NO3-(as N).

In other words, in this Example 2 projection, when the flow rate issufficient the fertilizer is added with irrigation water deliveredduring the 62.6 nine-hour irrigation periods from March 1 through May14, while in the Comparative Example B projection, the entire fertilizeris added only during the first nine-hour irrigation period on March 1st.

Another difference between the slug feeding and the present invention'scontinuous feeding is the rate of fertilizer addition. To fullyillustrate the magnitude of this difference, the feed rates are providedbelow.

Slug Feed—Feed Rate of Comparative Example B Projection (NitrateNitrogen):

In the slug feeding projection of Comparative Example B, the nitratenitrogen source is a commercial CAN-17 which has a nitrate compositionof 11.6 percent nitrate nitrogen and a density of 12.64 lbs./gal. (CANis an acronym for an aqueous solution of calcium nitrate and ammoniumnitrate.) The volume of CAN-17 used is: 150 acres×23.07 lbs./acre NO3-(as N)×100%/11.6%×1 gal./12.64 lbs. or 2360 gallons. The feed rate ofthis 2360 gallons, which is fed for a 9.0 hr. irrigation period, is:2360 gal./9.0 hrs.×1 hr./60 min. or 4.37 gal./min. (continuously fedthroughout a nine hour irrigation period).

Continuous Feed—Feed Rate of Example 2 Projection (Nitrate Nitrogen):

In the continuous feeding projection of Example 2 (again, the normalizedMarch 1 through May 14 feeding of 20.83 lbs./acre of nitrate nitrogen),the nitrate nitrogen is produced from three sources (again normalized):4.88 lbs./acre of nitrate nitrogen from the calcium nitrate feedstock;1.27 lbs./acre of nitrate nitrogen from the magnesium nitrate feedstock;and 14.68 lbs./acre of nitrate nitrogen from the nitric acid feedstock.These feedstocks have the following compositions and densities,respectively: 8.30% nitrate nitrogen and a density of 12.22 lbs./gal.for calcium nitrate; 7.30% nitrate nitrogen and a density of 11.29lbs./gal. for magnesium nitrate; and 15.1% nitrate nitrogen and adensity of 11.73 lbs./gal. for nitric acid. The volume of calciumnitrate feedstock used is 150 acres×4.88 lbs./acre NO3- (asN)×100%/8.3%×1 gal./12.22 lbs. or 723 gallons, which is chargedcontinuously during 62.6 irrigation periods at a feed rate of 723gal./62.6 cycles×1 cycle/9.0 hrs.×1 hr./60 min. or 0.0214 gal./min.

The volume of magnesium nitrate feedstock used is 150 acres×1.27lbs./acre NO3-(as N)×100%/7.2%×1 gal./11.29 lbs. or 234 gallons, whichis charged continuously during 62.6 irrigation periods at a feed rate of234 gal./62.6 cycles×1 cycle/9.0 hrs.×1 hr./60 min. or 0.00693 gal./min.

The volume of nitric acid feedstock used is 150 acres×14.68 lbs./acreNO3- (as N)×100%/15.1%×1 gal./11.73 lbs./gal. or 1243 gallons, which ischarged continuously during 62.6 irrigation periods at a feed rate of1243 gal./62.6 cycles×1 cycle/9.0 hrs.×1 hr./60 min. or 0.0368 gal./min.

The same magnitude of differences between conventional slug-fedfertigation and the continuous fertigation of the present inventionexists for every fertilizer component and for every irrigationtime-period (March through May, June through August and the like). Thenitrate nitrogen exemplified here and others below are merely presentedfor illustration purposes.

Further, as seen from this comparison using nitrate nitrogen as anexample, the continuous fertigation of the present invention is far moreefficient and effective than conventional slug-fed fertigation becausethe crop is receiving the right level of fertilizer continuously and nofertilizer is being wasted. In addition, if after the start of theirrigation time period, the weather conditions change from thosepredicted or there is a change in the nutrient needs of the crops forany reasons, the continuous fertigation of the present invention can bereadily adjusted to levels appropriate for the altered needs, while nopost-time-period-start adjustments can be made in a slug-fed fertigationbecause all of the fertilizers have been added to the soil.

Again, the traditional fertigation method is locked into the specificblend of fertilizer and cannot be varied from that blend. As a result ofthis rigidity the best source of fertilizer (i.e. urea (N) vs.ammoniacal (N) vs. nitrate (N)) is not always possible. In contrast,using the system and method of the present invention, any nutrient blendcan be made at any time providing the best fertigation profile withabsolutely no waste because the fertilizer is made in situ to exactlywhat the crop needs, instead of what is available to the grower from theformulations available from the fertilizer manufacturer.

The impact of the system and method of the present invention are againreflected in the feed rates. The conventional slug-fed feed rate is 4.37gal./min. for a nitrate nitrogen addition of 23.07 lbs./acre. Incontrast, using the system and method of the present invention, the feedrates are 0.0214 gal./min., 0.00629 gal./min., and 0.0368 gal./min. fornitrate nitrogen at a level of 20.83 lbs./acre, whereby the slug-fedrate is 204, 631 and 119 times higher respectively, althoughapproximately the same amount nitrate nitrogen is ultimately fed.

As seen in the above comparison, the system and method of the presentinvention can charge the crop-quality-enhancer feedstock to theirrigation system because so little crop-quality enhancer is beingcharged and/or reacted in the irrigation water at any time interval thatany exotherms or interaction between crop-quality enhancers and/or hard,alkaline irrigation water is dampened.

Slug Feed—Comparative Example B Projection (Potassium (as K2O)):

On March 15 potassium (as K2O) is slug fed into the irrigation system.Specifically, 100.0 lbs./acre potassium (as K2O) from a potassiumthiosulfate source is fed to 150 acres at a flow rate of 1200gallons/min. for this grower's normal 9.0 hour irrigation period. Thepotassium (as K2O) concentration in the irrigation water during thisslug fertigation process is: (100.0 lbs./acre potassium (as K2O)×150acres×1000 grams/2.2 lbs.)/(1200 gal./min.×9 hrs.×60 min./hr.×3.78liters/gal.×1000 ml/l liter) or 2784 ppm potassium (as K2O). This highconcentration of potassium (as K2O) cannot be fed simultaneously withthe slug feeding of other fertilizers because of incompatibilities withother fertilizers and the lack of available equipment.

The amount of water used during this slug fertigation process is, usingthe parameter that an ac-ft (acre-foot) is 325,851 gallons of water:1200 gal./min.×60 min./hr.×9 hrs. or 648,000 gal.×1 ac-ft/325,851 gal.or 1.99 ac-ft. The 1.99 ac-ft of water is distributed over 150 acres andtherefore the per-acre water distribution (1.99 ac-ft/150 acres) is0.0133 ac-ft/acre.

The next slug feed fertigation of potassium is September 30. The totalevenly-distributed irrigation water to be delivered during the secondhalf of March, April and May is 1 ac-ft. Therefore the amount ofirrigation water delivered during the period of March 16th (the dayafter the March 15th slug feeding) and May 31st (the day before the June1st slug feeding) is about “1 ac-ft/acre×(2.5 months/3.0 months)” or0.833 ac-ft/acre, and it will contain no potassium (as K2O) fertilizer.The total evenly distributed irrigation water to be delivered during theperiod from June 1 through August 31 is 2.5 ac-ft/acre and again willcontain no potassium (as K2O). The total evenly distributed irrigationwater to be delivered during the period from September 1 throughSeptember 29 (the day before the September 30th slug feeding) is about“0.5 ac-ft/acre×1.0 month/2 months)” or 0.25 ac-ft and it will againcontain no potassium (as K2O). As a result of this slug feed additionprofile, there are about [(3.583 ac-ft/acre)/0.0133 ac-ft)−1]” or 268.4irrigation periods during which no potassium (as K2O) is delivered withthe irrigation water between March 15 through September 29. Also, asdemonstrated above, to adequately irrigate the crop the above scenarioapproximately 269, 9-hour irrigation periods are required to irrigatethe almond crop. Since there are only 197 days between March 16 andSeptember 29 there are some days (hotter weather) when there are two9-hour irrigation periods (or the equivalent) to achieve the requiredamount of irrigation.

Continuous Feed—Example 2 Projection (Potassium (as K2O)):

A total of 50.0 lbs./acre potassium (as K2O) is continuously charged ata low concentration (18.5 ppm potassium (as K2O) as shown below) to theirrigation water distributed during each irrigation period during themonths of March, April and May (from March 1 up to, but not including,June 1). This low concentration of potassium (as K2O), unlike the highconcentration slug fed as described above, can be charged simultaneouslywith other low-concentration fertilizer feedstocks, and therefore thiscontinuous feeding begins on the desired March 1 date.

For purposes of comparison to the slug-fed projection above, only thepotassium (as K2O) charged, and the irrigation water delivered, duringthe time period of between March 15 and May 31 is compared. Thecomparative (normalized) amount of potassium (as K2O) charged betweenMarch 15 and May 31 is 41.7 lbs./acre potassium (as K2O). The potassium(as K2O) concentration in the irrigation water during this continuousfertigation process is: (41.7 lbs./acre×150 acres×1000 grams/2.2lbs.)/(0.833 ac-ft/acre×325,851 gal./ac-ft×3780 ml/gal.×150 acres) or18.5 ppm potassium (as K2O).

In other words, in this Example 2 projection, potassium is continuouslydelivered with the 0.833 ac-ft of irrigation water delivered during the62.6 nine-hour irrigation periods from March 1 through May 31, while inthe Comparative Example B projection, the entire fertilizer is addedonly during the first nine-hour irrigation period. Further, thepotassium (as K2O) charged in Example 2 is 50% less than in ComparativeExample B because, given the rate of potassium uptake by a plant, this50% lower amount is sufficient to maintain a constant supply ofpotassium in the wetted root zone throughout the March 1 through May 31time period. In contrast, the higher amount of potassium is required inComparative Example B to at least partially compensate for the amount ofpotassium in the single slug feeding that is later washed away from thewetted root zone before uptake by a plant.

Again, another difference between the slug feeding of ComparativeExample B and the present invention's continuous feeding of Example 2 isthe rate of fertilizer addition. Again to fully illustrate the magnitudeof this difference, the feed rates are provided below.

Slug Feed—Feed Rate of Comparative Example B Projection (Potassium (asK2O)):

In the slug feeding projection of Comparative Example B, the source ofthe 100 lbs./acre of potassium (as K2O) is a potassium thiosulfate(K2SSO3) feedstock which is 25.0 percent potassium (as K2O) and has adensity of 12.64 lbs./gal. The volume of the potassium thiosulfatefeedstock used is: 150 acres×100.0 lbs./acre potassium (asK2O)×100%/25.0%×1 gal./12.64 lbs. or 4747 gallons. This 4747 gallons isthen applied to the 150 acres in a 9.0 hr. period which means the feedrate is: 4747 gal./9.0 hrs.×1 hr./60 min.=8.79 gal./min. (continuouslythroughout a nine hour irrigation period).

Continuous Feed—Feed Rate of Example 2 Projection (Potassium (as K2O)):

In the continuous feeding projection of Example 2, which again will beillustrated as the normalized (March 15 through May 31) feeding of 41.7lbs. of potassium (as K2O), the source, a single source, is a potassiumhydroxide feedstock having 42% potassium (as K2O) and a density of 12.51lb./gal. The volume of potassium hydroxide feedstock used is: 150acres×41.7 lbs./acre potassium (as K2O)×100%/42%×1 gal./12.51 lbs. or1784 gallons. The feed rate of this 1784 gallons, which is chargedcontinuously for delivery to 150 acres 62.6 nine-hour irrigationperiods, is: 1784 gal./62.6 periods×1 period/9.0 hrs.×1 hr./60 min. or0.0528 gal./min.

Therefore the feed rate of the present invention's Example 2 projectionis 0.0558/8.79, or 0.6%, that of the feed rate of the ComparativeExample B projection. In other words, the feed rate of the ComparativeExample B projection is 8.79/0.0558, or 158% faster than the feed rateof the present invention's Example 2 projection. In other words, theconventional slug-feeding feed rate is 8.79 gal./min. for a potassiumaddition of 100.0 lbs./acre (as K2O), the continuous-feed feed rate ofthe present invention is 0.0528 gal./min. for a potassium addition of50.0 lbs./acre (as K2O), and therefore the slug-feed is (8.79gal./min)/(0.0528 gal./min.) or 158 times faster.

Continuous Feed—Responsive to Shifting Conditions, Example 2 Projection(Potassium (as K2O)):

Although this Example 2 projection for potassium (and likewise any ofthe chemicals being added or produced) for a distinct irrigation period,it is easily seen that if the weather changes or a crops need changestheir nutrient profile for any reason, the method and system of thepresent invention is, or preferably is, responsive to those changes. Incontrast, once a single shot (slug feeding) of fertilizer is deliveredto the crop as in the conventional method (such as shown in ComparativeExample B), no responsive changes can be made because everything hasalready added to the soil. The method of the present invention, unlikethe conventional slug feeding method, is not locked in to anyformulation or any feed rate of components. In other words, any blendcan be made at any time providing the best fertigation profile withabsolutely no waste because the fertilizer is made on site to exactlywhat the crop needs, instead of what formulation is available to thegrower from the fertilizer manufacturer.

Continuous Feed—Absence of Plugging, Example 2 Projection (Potassium (asK2O)):

Adding a KOH feedstock to an irrigation system in any conventionalmanner would cause severe plugging of the irrigation system and bedetrimental to plant grower because it is extremely alkaline pH (>14).In the continuous feeding method of the present invention, the potassiumhydroxide is neutralized with an acid. If that acid were simplyconcentrated H2SO4 (98%), and the neutralization reaction that shown inEq. 2 above, the amount of acid used would be: 62.5 lbs/acre (asK2O)×150 acres×(98.0 g/mole)/(94.2 g/mole)×100%/98% H2SO4×1 gal./15.30lbs. or 650 gallons, which would be charged at a rate of: 650 gal./62.6cycles×1 cycle/9.0 hrs.×1 hr./60 min. or 0.0192 gal./min. (over 62.6fertigation periods).

In reality the neutralization is much more complicated than just asimple neutralization of 50 percent potassium hydroxide withconcentrated sulfuric acid because, as outlined above, there aremultiple crop-quality enhancers being simultaneously charged to producemultiple fertilizers, and therefore there are multiple reactions (andpossibly non-reactive dissolutions) occurring simultaneously. The uniquemixture of reaction, and possibly non-reactive dissolution, productsconsists of a solution of hydrogen ions, potassium cations, ammoniumcations, nitrate anions, phosphate anions, sulfate anions and urea/ureacarbamate. The entire reaction profile of the acids and bases beingcharged from March 1 through May 31 is provided in Example 2.1 below.

Example 2.1 Continuous Feed—Acid/Base Reaction Profile

Since (as shown above) there is considerably more alkalinity being addedto the irrigation, to avoid the massive plugging that ordinarily wouldoccur, concentrated sulfuric acid is added to neutralize the excessalkalinity (achieve a neutral pH) in the approximate amount of: (1267.2OH— moles/acre)−(764.8 H+ moles/acre) or 502.4 H+ moles/acre. Thatrequires: 502.4 H+ moles/acre×98 g/mole×(H2SO4/2H+)×100%/98%×2.2lbs./1000 g or 55.3 lbs./acre. The volume amount is 55.3 lbs./acre×150acres×1 gal./15.30 lbs. or 541.8 gallons.

During the time period of March 1 through May 31, there are 75.2irrigation periods (1.0 ac-ft/acre/(0.0133 ac-ft), and the sulfuric acidfeed rate is: 541.8 gal./75.2 cycles×1 cycle/9.0 hrs.×1 hr./60 min. or0.0133 gal./min. (over 75.2 fertigation applications). In practice, thesulfuric acid pump is preferably initially set for about 120 percent ofthe calculated feed rate to achieve the desired pH because of the waterquality of the irrigation water. (Typical irrigation water contains 100to 500 ppm total alkalinity (as CaCO3)). This is a “rough”irrigation-water neutralization because, as mentioned elsewhere herein,the system of the present invention automatically senses the water pHand automatically corrects the water pH by adjustment of acid feed rateto assure the desired pH is continuously maintained.

In contrast to these simultaneous additions using the method and systemof the present invention, if a grower attempted to simultaneously addthe equivalent amounts of potassium hydroxide, ammonium hydroxide, urea,sulfuric acid, phosphoric acid and nitric acid, by the conventionalslug-feeding method, an extreme exotherm would develop. This exothermwould be dangerous to both the irrigation equipment and equipmentsystem, as well as the operator (irrigator). For this reason, thefertigation-addition of these chemicals in an agricultural environment,outside of the system and method of the present invention, would bewholly unreasonable and would not be attempted. In other words, themethod and system of the present invention mitigate the conditions thatgenerate huge exotherms by mixing and, in instances such as in thisexample, reacting these chemicals under conditions approaching infinitedilution.

Slug Feed—Comparative Example B Projection (Calcium, Magnesium,Phosphorus):

This projection does not take into account the water-quality factor,which is discussed separately below.

On March 1 calcium (as Ca) is slug fed into the irrigation system.Specifically, 17.50 lbs./acre calcium (as Ca) from a CAN-17 source isfed to 150 acres at a flow rate of 1200 gallons/min. for this grower'snormal 9.0 hour irrigation period. (CAN is an acronym for an aqueoussolution of calcium nitrate and ammonium nitrate.) The calcium (as Ca)concentration in the irrigation water during this slug fertigationprocess therefore is: (17.50 lbs./acre calcium (as Ca)×150 acres×1000grams/2.2 lbs.)/(1200 gal./min.×9 hrs.×60 min./hr.×3.78 liters/gal.×1000ml/1 liter) or 487.1 calcium (as Ca). The amount of water used duringthis slug fertigation process is, using the parameter that an ac-ft(acre-foot) is 325,851 gallons of water: 1200 gal./min.×60 min./hr.×9hrs. or 648,000 gal.×1 ac-ft/325,851 gal. or 1.99 ac-ft.

The 1.99 ac-ft of water is distributed over 150 acres and therefore theper-acre water distribution (1.99 ac-ft/150 acres) is 0.0133 ac-ft/acre.The next slug feed fertigation is July 1. The total evenly-distributedirrigation water to be delivered during March, April and May is 1.0ac-ft. The total evenly distributed irrigation water to be deliveredduring June is “[(1.0 month/3.0 months)×2.5 ac-ft/acre]” or 0.833ac-ft/acre. Therefore, the amount of irrigation water delivered duringthe period of March 1 through June 30 (the day before the July 1 slugfeeding) is about 1.833 ac-ft/acre. Again, this grower's normalirrigation period is 9 hours. Therefore after the single slug feed offertilizer there are about “[(1.833 ac-ft/acre)/(0.0133 ac-ft/acre)−1]”or 136.8 irrigation periods on which no calcium fertilizer is deliveredwith the irrigation water.

No magnesium based material is added via the irrigation system in thisComparative Example B because there is no commercially practical sourceof a liquid-based magnesium fertilizer that is available to this grower.To satisfy a magnesium deficiency this grower has field-spread soliddolomite in the past, which has its problems, as mentioned earlier.

As seen from the above, the calcium and phosphorus fertilizers are slugfed on different days, namely the calcium fertilizer on March 1 and July1, and the phosphorus fertilizer on March 30 and September 15. Thesefertilizers are not slug fed simultaneously because the slug-fed calciumconcentration is vastly higher than the threshold level beyond whichprecipitation will occur when added together with phosphate. In moredetail, when added as shown above, namely 17.5 lbs/acre calcium (as Ca)with a water usage of 0.0133 ac-ft/acre (on both March 1 and July 1),the calcium addition rate is 487.1 ppm Ca+2 or 1218 ppm (as CaCO3).(Using the same calculation method, the addition rate of 35.00 lbs/acrephosphate (as P2O5) on March, 30 and September 15 is 1304 ppm PO4-3.)The maximum amount of calcium that can be present in the irrigationwater concomitantly with that phosphate-based fertilizer, at a water pHof 6.5, is 4.4 ppm calcium (as CaCO3). The 1218 ppm calcium (as CaCO3)addition rate is about 275 times higher than that threshold, and even ifthe addition rates were lowered 50% via calcium and phosphate additionson four, rather than two, fertigation days, the calcium addition ratewould still be vastly higher than the solubility threshold.

Continuous Feed—Example 2 Projection (Calcium, Magnesium):

This projection does not take into account the water-quality factor,which is discussed separately below.

These projections are first set out here as if the phosphoric acidaddition during the various time periods did not occur. The profile withphosphoric acid addition are described thereafter.

A total of 8.33 lbs./acre of calcium (as Ca) is continuously charged tothe irrigation water distributed during each irrigation period duringthe months of March, April and May (from March 1 up to, but notincluding, June 1). It is noted that any fertilizer feedstock, andtherefore the calcium, is delivered to the crop at the time it isneeded, and not merely when a tank or manpower is available as seen whenconventional slug-fed fertigation techniques are used. The presentinvention is also illustrated below in this Example 2 for the subsequentirrigation periods that have a different water usage.

The calcium (as Ca) concentration in the irrigation water during thecontinuous fertigation process from March 1 through May 31 (a 1.0ac-ft/acre water usage period) is: (8.33 lbs./acre×150 acres×1000grams/2.2 lbs.)/(1.0 ac-ft/acre×325,851 gal./ac-ft×3780 ml/gal.×150acres) or 3.07 ppm calcium (as Ca).

The calcium (as Ca) concentration in the irrigation water during thecontinuous fertigation process from June 1 through August 31 (a 2.5ac-ft/acre water usage period) is: (8.33 lbs./acre×150 acres×1000grams/2.2 lbs.)/(2.5 ac-ft/acre×325,851 gal./ac-ft×3780 ml/gal.×150acres) or 1.23 ppm calcium (as Ca).

In this projection, and in the system and method of the presentinvention generally, the rate of chemical addition does notautomatically change when the irrigation water usage or flow ratechanges (unless the system is programmed to do so). When the amount offertilizer (here, calcium (as Ca)) delivered during a 9 hour irrigationperiod is held constant regardless of the water usage, the concentrationof calcium (as Ca) in the irrigation water is lower when the volume ofirrigation water delivered is higher (because there are many more 9-hourirrigation periods, perhaps 2 or more per day) as seen here for the June1 through August 31 time period. In fact, it is not uncommon for growersto irrigate 24 hours per day or 2.67, 9-hour, irrigation periods, in oneday because of very high temperatures and the resultant high evaporativelosses of water. This is an important distinction because this is theperiod where the plant/crop requires less or no nutrients, and a lowerfertilizer level can be added providing better usage of the fertilizerby the plant as well as better economics. In addition, in contrast tothe slug fed method, magnesium can be, and is, added through theirrigation system in this projection. A total of 1.33 lbs./acre ofmagnesium (as Mg) is continuously charged to the irrigation waterdistributed during each irrigation period during the months of March,April, May, June, July and August (from March 1 up to, but notincluding, September 1). Unlike conventional fertigation methods, any ofthe fertilizer nutrients or crop-quality enhancers and any combinationsof these nutrients or crop-quality enhancers can be chargedsimultaneously using the system and the method of the present inventionprovided that no solubility limits are exceeded. Therefore, as seen inthis projection, and generally, magnesium (as Mg) can, and is, deliveredto the crop in the proper ratio to calcium when the crop needs it.

The magnesium (as Mg) concentration in the irrigation water during thecontinuous fertigation process from March 1 through May 31 (a 1.0ac-ft/acre water usage period) is: (1.33 lbs./acre×150 acres×1000grams/2.2 lbs.)/(1.0 ac-ft/acre×325,851 gal./ac-ft×3780 ml/gal.×150acres) or 0.49 ppm magnesium (as Mg).

The magnesium (as Mg) concentration in the irrigation water during thecontinuous fertigation process from June 1 through August 31 (a 2.5ac-ft/acre water usage period) is: (1.33 lbs./acre×150 acres×1000grams/2.2 lbs.)/(2.5 ac-ft/acre×325,851 gal./ac-ft×3780 ml/gal.×150acres) or 0.20 ppm magnesium (as Mg).

Further, the calcium charged in this projection is less than inComparative Example B because, given the rate of calcium uptake by aplant, these lower amounts are sufficient to maintain a constant supplyof calcium in the wetted root zone throughout the time period. Incontrast, the higher amounts of calcium are required in ComparativeExample B to at least partially compensate for the amount of calcium inthe single slug feeding and mechanical application respectively which islater washed away from the wetted root zone before uptake by a plant.

Again, as mentioned elsewhere herein, the system and method of thepresent invention substantially eliminate the problems that arise fromincompatibilities between fertilizers because solubility limitsgenerally cannot be exceeded when feeding continuously at low levels.When conventional slug-feeding fertigation methods are used, thesolubility limits between incompatible fertilizers are exceeded, andtherefore such fertilizers must be fed on different days, and then onlyafter washing out the feeding equipment. As an example, both calcium andmagnesium fertilizers normally form very insoluble calcium/magnesiumphosphates in the presence of phosphate fertilizers, and thereforeneither calcium or magnesium fertilizers can be slug fed together withphosphate fertilizers; doing so would cause massive, catastrophicplugging of the entire irrigation system.

Continuous Feed—Example 2 Projection (Calcium, Magnesium, Phosphorus):

The Example 2 calcium and magnesium projections above provide the amountof calcium and magnesium to be added continuously, and theconcentrations of calcium and magnesium in the irrigation water for twolevels of water usage (volume of irrigation water per acre delivered tothe soil in a nine-hour irrigation period) when calcium and magnesiumare continuously charged. Those concentrations of calcium and magnesium(continuously charged) are used in this projection as the basis orgroundwork for the calculation of calcium and magnesium concentrationswhen fed at cyclic (recurring) intervals to avoid incompatibilities withphosphate.

This projection provides a profile regarding the calcium and magnesiumfeeding simultaneously with a phosphate crop-quality enhancer, whichwould be charged as follows. From March 1 up to, but not including, June1, the addition of 30.00 lb/acre phosphate (as P2O5), given a waterusage of 1.00 ac-ft/acre, provides a concentration of 14.81 ppm PO4-3 inthe irrigation water. From September 1 up to, but not including,November 1, the addition of 20.00 lb/acre phosphate (as P2O5), given awater usage of 0.50 ac-ft/acre, provides a concentration of 19.75 ppmPO4-3 in the irrigation water.

When simultaneously feeding both a calcium and the above-indicatedamount of phosphate crop-quality enhancer at a water pH of 6.5 using themethod and system of the present invention, the maximum amount ofcalcium that can be present in the irrigation water is 94.8 ppm calcium(as Ca) for 14.81 ppm PO4-3 and 78.2 ppm calcium (as Ca) for 19.75 ppmPO4-3. Exceeding that maximum will, due to calcium/phosphate interactionand/or precipitation, will lead to plugging of the irrigation system. Asindicated above, the calcium (as Ca) concentration in the irrigationwater is 3.08 ppm calcium (as Ca) during the continuous fertigationprocess from March 1 through May 31 and is 6.13 ppm calcium (as Ca)during the continuous fertigation process from September 1 throughOctober 31. (There is no addition of phosphate June through August.) Thecalcium-concentration threshold above which there is a irrigation-systemplugging problem, is thirty-six times higher than the highest calciumconcentration used in this projection.

Slug Feed—Comparative Example B Projection (Calcium, Phosphorus, WaterQuality):

The irrigation water at this site contains 150 ppm calcium (as CaCO3).As noted in the slug-feed projection above, calcium and phosphorus arefed on separate fertigation days to avoid interactions/precipitationarising from calcium and phosphate concentrations. That projectiondisregarded the 150 ppm calcium (as CaCO3) already present in theirrigation water.

The profile above provides fertigations on March 30 and September 15that feed 1304 ppm phosphate (as PO4-3) and feeds no calcium because thecalcium solubility threshold is 4.4 ppm calcium (as CaCO3). The 150 ppmcalcium (as CaCO3) already present in the irrigation water is muchhigher than the 4.4 ppm calcium (as CaCO3) threshold, and therefore ifthat profile was followed, precipitation and plugging of the irrigationsystem would occur despite the precaution of not simultaneously slugfeeding calcium and phosphate.

Continuous Feed—Example 2 Projection (Calcium, Phosphorus, WaterQuality):

As noted above, the irrigation water at this site contains 150 ppmcalcium (as CaCO3) or 60 ppm (as Ca). As noted in the projection above,the continuous feed method and system of the present invention providesa concentration of 14.81 ppm PO4-3 in the irrigation water from March 1up to, but not including, June 1, and a concentration of 19.75 ppm PO4-3in the irrigation water from September 1 up to, but not including,November 1. The calcium concentration thresholds for these time periodsare 94.8 and 78.2 ppm calcium (as Ca) respectively, and the calciumconcentrations from the continuous fertigations are 3.07 and 6.13 ppmcalcium (as Ca) respectively. The addition of 60 ppm calcium (as Ca)already present in the irrigation water raises the calciumconcentrations to about 63.1 and 66.2 ppm calcium (as Ca) respectively,which remain well below the thresholds of 94.8 and 78.2 ppm calcium (asCa) respectively. In other words, despite the high calcium levels in theirrigation water itself, the continuous feed method and system of thepresent invention permits calcium and phosphate to be charged to theirrigation system simultaneously because the calcium-concentrationthreshold is about 1.5 times higher than the actual calciumconcentration from March 1 up to, but not including, June 1, and thecalcium-concentration threshold is about 1.2 times higher than theactual calcium concentration from is September 1 up to, but notincluding, November 1.

An Extrapolation of Example 2 Projection (Potassium (as K2O)):

The acids charged in the Example 2 projection are 116.7 lbs./acreconcentrated nitric acid (15.1-0-0) and 55.24 lbs./acre concentratedphosphoric acid (0-54.3-0). The bases charged in the Example 2projection are 119.0 lbs. of concentrated potassium hydroxide(0-0-42.0), 104.2 lbs./acre of concentrated ammonium hydroxide(24.0-0-0), and 108.7 lbs./acre of urea (23-0-0). Based on the reactionsof these acids and bases, the amount of concentrated sulfuric acidrequired to achieve a neutral pH can be these approximated from theacidity and alkalinity contributions from these sources. Acidity due tonitric acid addition is 116.7 lbs./acre×68%×1 mole/63 g×1000 g/2.2 lbs.or 572.6 moles H+/acre. The acidity due to phosphoric acid is 55.24lbs./acre×75%×1 mole/98 g×1000 g/2.2 lbs. or 192.2 moles H+/acre (thisassumes that at a pH of 6.5 to 7.0 (typical operating pH) the phosphoricacid only contributes one proton toward neutralization). The alkalinitydue to potassium hydroxide is 119.0 lbs./acre×50%×1 mole/56.1 g×1000g/2.2 lbs. or 482.1 moles OH—/acre. The alkalinity due to ammoniumhydroxide is 104.2 lbs./acre×28.5%×1 mole/35 g×1000 g/2.2 lbs. or 385.7moles OH—/acre. The alkalinity due to urea is 108.7 lbs./acre×48.5%×1mole/60 g×1000 g/2.2 lbs. or 399.4 moles OH—/acre (noting that althoughurea is a weak base it will consume acid just like the strong bases suchas potassium hydroxide and ammonium hydroxide). The total acidity is:(572.6 H+ moles/acre)+(192.2H+ moles/acre) or 764.8 H+ moles/acre. Thetotal alkalinity is: (482.1 OH— moles/acre)+(385.7 OH—moles/acre)+(399.4 OH— moles/acre) or 1267.20H-moles/acre.

Comments on the In-Situ Fertilizer Manufacture Embodiment

In certain embodiment, the method and system of the present inventioncan use all or any of the raw materials that are used to manufacture theabove-described commercial fertilizers, namely ammonia, potassiumhydroxide, urea, nitric acid, sulfuric acid, phosphoric acid, calciumnitrate and magnesium nitrate, right at the irrigation site. When theseraw materials are reacted utilizing the irrigation system the followingreactions take place to some extent until an equilibrium is reached:

-   -   1). HNO3+KOH→KNO3+H2O+heat of reaction    -   2). HNO3+NH3→NH4NO3+heat of reaction    -   3). HNO3+urea→[urea][HNO3]+heat of reaction    -   4). H2SO4+KOH→KHSO4+H2O+heat of reaction    -   5). H2SO4+2 KOH→K2SO4+2H2O+heat of reaction    -   6). H2SO4+NH3→(NH4)HSO4+heat of reaction    -   7). H2SO4+2NH3→(NH4)2SO4+heat of reaction    -   8). H2SO4+urea→[urea][H2SO4]+heat of reaction    -   9). H2SO4+2 urea→[urea]2-[H2SO4]+heat of reaction    -   10). H2SO4+KOH+NH3→K(NH4)SO4+H2O+heat of reaction    -   11). H3PO4+KOH→KH2PO4+H2O+heat of reaction    -   12). H3PO4+2 KOH→K2HPO4+2H2O+heat of reaction    -   13). H3PO4+3 KOH→K3PO4+3 H2O+heat of reaction    -   14). H3PO4+NH3→(NH4)H2PO4+heat of reaction    -   15). H3PO4+2NH3→(NH4)2HPO4+heat of reaction    -   16). H3PO4+3 NH3→(NH4)3PO4+heat of reaction    -   17). H3PO4+urea→[urea][H3PO4]+heat of reaction    -   18). H3PO4+NH3+KOH→K(NH4)HPO4+H2O+heat of reaction    -   19). H3PO4+2NH3+KOH→K(NH4)2PO4+H2O+heat of reaction    -   20). H3PO4+NH3+2 KOH→K2(NH4)PO4+2H2O+heat of reaction    -   21). Ca(NO3)2—No reaction    -   22). Mg(NO3)2—No reaction

In solution these transient compounds immediately dissociate into thefollowing ionic and neutral species with the formation of additionalheat: (a) the cations NH4+, H+, K+ and Ca+2; (b) the anions NO3-,H2PO4-, HPO4-2, PO4-3, HSO4- and SO4-; and neutral urea, and these arethe species which ultimately form the basis of the nutrients that theplant uses.

In the in-situ fertilizer manufacture embodiment of the presentinvention, if the growing conditions (and therefore the desired nutrientaddition) change, the amounts and ratios of the nutrients being chargedcan be changed to best suit conditions at a moments notice.

Example 3 and Comparative Example C Projections

The fertigation projections for a ranch having 453 acres of almondsunder cultivation were developed using conventional fertigationtechniques in Comparative Example C and, for comparison, the method andsystem of the present invention in Example 3. The expected irrigationperiod for the crop is March 1 through October 30. The irrigation systemon this ranch does not allow simultaneous irrigation of the entire 453acres. Instead, the 453 acres are irrigated in five portions orsections, and a set of valves switches the water flow from one sectionto another. Fertigation of course must likewise be conducted in fiveportions or sets, that is, one set for each of the five sections.Slug-fed fertigation for a set typically requires feeding the materialinto the irrigation system for a time period of six to seven hours, andthen this is repeated the following day for the next set, until allsections are fertigated in five sets usually over a five-day timeperiod. The continuous-feed fertigation of Example 3 is of courseongoing whenever the irrigation system is active and is at theappropriate water-flow level as described elsewhere.

The nutrient profiles and the materials and amounts thereof (lb./acre)to be fed for the conventional slug-fed fertigation with commercialfertilizers of Comparative Example C and the present invention'scontinuous in-situ manufacturing fertigation embodiment of Example 3 areprovided below.

Comparative Example C Conventional Slug-Fed Fertigation with CommercialFertilizers

Meeting the nutrient profiles below requires thirteen fertigations (eachdesignated by the first date of a series of five fertigation sets) andthe addition of a single commercial fertilizer at a single feed pointalong the irrigation system's main line for each fertigation. The numberof fertigation sets therefore is sixty-five. Due to the inflexibility ofnutrient ratios of the commercial fertilizers, meeting the nutrientprofiles requires exceeding at least one of the profiles. In addition,the total poundage fed to the system is significantly higher than thatof Example 3.

Profiles:

Nitrogen as (N) Profile:

200 lbs./acre Total Nitrogen. The nitrogen will be obtained from avariety of nitrogen-containing fertilizer solutions: Commercial(7-21-0); Commercial (10-34-0); Commercial (15-0-0); Commercial(32-0-0); Commercial (20-0-0); Commercial (4-6-10); and Commercial(17-0-0+8.8 Ca). This is to be added during the following intervals:March 1 through May 31, 125 lbs./acre of total nitrogen (as N); June 1through August 31, 25 lbs./acre of total nitrogen (as N); September 1through October 30, 50 lbs./acre of total nitrogen (as N).

Phosphorus (as P2O5) Profile:

80 lbs./acre Total Phosphorus. The phosphorus will be obtained from avariety of commercially available fertilizers: Commercial (7-21-0);Commercial (4-6-10); Commercial (10-34-0); and Commercial (0-21-0). Thisis to be added during the following intervals: March 1 through May 31,40 lbs./acre of total phosphorus (as P2O5); June 1 through August 31, 0lbs./acre of total phosphorus (as P2O5); and September 1 through October30, 40 lbs./acre of total phosphorus (as P2O5).

Potassium (as K2O) Profile:

180 lbs./acre Total Potassium. The potassium will be obtained fromvariety of commercially available fertilizers: Commercial (0-0-25);Commercial (4-6-10); and Commercial (0-0-5). This is to be added duringthe following intervals: March 1 through May 31, 100 lbs./acre of totalpotassium (as K2O); June 1 through August 31, 25 lbs./acre of totalpotassium (as K2O); September 1 through October 30, 55 lbs./acre oftotal potassium (as K2O).

Calcium (as Ca) Profile:

35 lbs./acre Total Calcium. The calcium will be obtained from acommercially available fertilizer (17-0-0 +8.8 Ca). This is to be addedduring the following intervals: March 1 through May 31, 17.5 lbs./acreof total calcium (as Ca); June 1 through August 31, 0 lbs./acre of totalcalcium (as Ca); September 1 through October 30—17.5 lbs./acre of totalcalcium (as Ca).

pH Profile:

No adjustment (pH is the pH of the incoming irrigation water, which isabout 7.8, which might be somewhat modified by the slug-feedings).

Commercial Fertilizers Fed and Nutrients Provided:

March 1 Commercial Fertilizer Fed and Nutrients Provided:

Slug-feed of 142.9 lbs./acre of a blended commercial mixture calledStructure® (Structure® is a registered trademark of Actagro, LLC ofBiola, Calif.) which is derived from ammonia, urea, ammonium nitrate,phosphoric acid and other non-fertilizer ingredients (7-21-0). Thisslug-feed provides: (a) 8.6 lbs./acre of ammoniacal nitrogen (as N); (b)0.4 lbs./acre of nitrate nitrogen (as N); (c) 1.0 lbs./acre of ureanitrogen (as N); and (d) 30.0 lbs./acre of phosphorus (as P2O5).

March 15 Commercial Fertilizer Fed and Nutrients Provided:

Slug-feed 333.2 lbs./acre of a commercial mixture called K-Mend®(K-Mend® is a registered trademark of Best Sulfur Products, Inc. ofFresno, Calif.) which is derived from potassium thiosulfate (0-0-25).This slug-feed provides 83.3 lbs./acre of potassium (as K2O).

March 30 Commercial Fertilizer Fed and Nutrients Provided:

Slug-feed of 198.9 lbs./acre of a blended commercial mixture (calledCAN-17) which is derived from ammonium nitrate and calcium nitrate(17-0-0+8.8 Ca). This slug-feed provides: (a) 10.8 lbs./acre ofammoniacal nitrogen (as N); (b) 23.1 lbs./acre of nitrate nitrogen (asN); and (c) 17.5 lbs./acre of calcium (as Ca).

April 15 Commercial Fertilizer Fed and Nutrients Provided:

Slug-feed of 126.7 lbs./acre of a blended commercial mixture (calledN-pHuric 15/49) which is derived from urea and sulfuric acid (15-0-0).This slug-feed provides (a) 19.0 lbs./acre of urea nitrogen (as N).

May 1 Commercial Fertilizer Fed and Nutrients Provided:

Slug-feed of 167.2 lbs./acre of a blended commercial mixture calledCache® (Cache® is a registered trademark of Actagro, LLC of Biola,Calif.) which is derived from ammonia, urea, ammonium nitrate,phosphoric acid and potassium chloride (4-6-10). This slug-feedprovides: (a) 3.7 lbs./acre of ammoniacal nitrogen (as N); (b) 1.0lbs./acre of nitrate nitrogen (as N); (c) 2.0 lbs./acre of urea nitrogen(as N); (d) 10.0 lbs./acre of phosphorus (as P2O5); and (e) 16.7lbs./acre of potassium (as K2O).

May 15 Commercial Fertilizer Fed and Nutrients Provided:

Slug-feed 173.4 lbs./acre of a blended commercial mixture (calledUAN-32) which is derived from ammonium nitrate and urea (32-0-0). Thisslug-feed provides (a) 13.4 lbs./acre of ammoniacal nitrogen (as N); (b)13.4 lbs./acre of nitrate nitrogen (as N); and (c) 28.6 lbs./acre ofurea nitrogen (as N).

June 15 Commercial Fertilizer Fed and Nutrients Provided:

Slug-feed 100.0 lbs./acre of a commercial mixture called K-Mend®(K-Mend® is a registered trademark of Best Sulfur Products, Inc. ofFresno, Calif.) which is derived from potassium thiosulfate (0-0-25).This slug-feed provides 25.0 lbs./acre of potassium (as K2O).

July 1 Commercial Fertilizer Fed and Nutrients Provided:

Slug-feed 125.0 lbs./acre of a blended commercial mixture (called AN-20)which is derived from ammonium nitrate (20-0-0). This slug-feed provides(a) 12.5 lbs/acre of ammoniacal nitrogen (as N); and (b) 12.5 lbs/acreof nitrate nitrogen (as N).

September 1 Commercial Fertilizer Fed and Nutrients Provided:

Slug-feed 198.9 lbs./acre of a blended commercial mixture (calledCAN-17) which is derived from ammonium nitrate and calcium nitrate(17-0-0+8.8 Ca). This slug-feed provides (a) 10.8 lbs./acre ofammoniacal nitrogen (as N); (b) 23.1 lbs./acre of nitrate nitrogen (asN); and (c) 17.5 lbs./acre of calcium (as Ca).

September 15 Commercial Fertilizer Fed and Nutrients Provided:

Slug-feed 88.2 lbs./acre of a blended commercial mixture (called liquidammonium polyphosphate) which is derived from ammonium phosphate(10-34-0). This slug-feed provides (a) 8.8 lbs./acre of ammoniacalnitrogen (as N); and (b) 30.0 lbs./acre of phosphorus (as P2O5).

October 1 Commercial Fertilizer Fed and Nutrients Provided:

Slug-feed 47.6 lbs./acre of a blended commercial mixture (called DPG0-21-0) which is derived from phosphoric acid and other non-fertilizeringredients (0-21-0). This slug-feed provides 10.0 lbs./acre ofphosphorus (as P2O5).

October 15 Commercial Fertilizer Fed and Nutrients Provided:

Slug-feed 48.6 lbs./acre of a blended commercial mixture calledN-pHuric® 15/49 which is derived from urea and sulfuric acid (15-0-0).This slug-feed provides (a) 7.3 lbs./acre of urea nitrogen (as N).

October 30 Commercial Fertilizer Fed and Nutrients Provided:

Slug-feed 1100.0 lbs./acre of a blended commercial mixture calledPotassium sulfate solution which is derived from potassium sulfate(0-0-5). (The more convenient source, namely 220 lbs/acre of acommercial mixture called K-Mend® which is derived from potassiumthiosulfate (0-0-25) was not available to the grower at the time it wasneeded.) This slug feed provides 55.0 lbs./acre of potassium (as K2O).

Example 3 Continuous In-Situ Manufactured Fertigation Embodiment of thePresent Invention

The nutrient profiles (below) are satisfied with a continuous feeding ofa plurality of co-reactant crop-quality enhancers and any includednon-co-reactant crop-quality enhancers, the composition of which isdifferent during three continuous-fertigation intervals (each designatedby the first and last dates of the interval) wherein up to sevenco-reactant and non-co-reactant crop-quality enhancers are simultaneouscharged at separate, but proximate, feed points along the irrigationsystem's main line. These co-reactant crop-quality enhancers, uponintermixing and reacting within the main line, and upon intermixing withany included non-co-reactant crop-quality enhancers, produce the presentinvention's fertilizer crop-quality enhancers. The in-situ manufacturingmethod embodiment of the present invention provides the flexibility withlimitless and continuous fertigations (for every irrigation set) andmatches, without exceeding, the nutrient profiles. In other words,unlike Comparative Example C's conventional fertigation in which, due tothe inflexibility of nutrient ratios of the commercial fertilizers,meeting the nutrient profiles requires exceeding at least one of theprofiles, the continuous crop-quality-enhancement fertigation embodimentof the present invention ensures that all nutrient profiles are met andnone are exceeded. In addition, the total poundage fed to the system issignificantly lower.

Profiles:

Nitrogen (as N) Profile:

200 lbs./acre Total Nitrogen. The nitrogen will be obtained from calciumnitrate solution, concentrated nitric acid, ammonia and an ureasolution. This is to be added continuously during the followingintervals: March 1 through May 31, 125 lbs./acre of total nitrogen (asN); June 1 through August 31, 25 lbs./acre of total nitrogen (as N); andSeptember 1 through October 30, 50 lbs./acre of total nitrogen (as N).

Phosphorus (as P2O5) Profile:

80 lbs./acre Total Phosphorus. The phosphorus will be obtained fromconcentrated phosphoric acid. This is to be added continuously duringthe following intervals: March 1 through May 31, 40 lbs./acre of totalphosphorus (as P2O5); June 1 through August 31, 0 lbs./acre of totalphosphorus (as P2O5); September 1 through October 30, 40 lbs./acre oftotal phosphorus (as P2O5).

Potassium (as K2O) Profile:

180 lbs./acre Total Potassium. The potassium will be obtained fromconcentrated potassium hydroxide. This is to be added continuouslyduring the following intervals: March 1 through May 31, 100 lbs./acre oftotal potassium (as K2O). June 1 through August 31, 25 lbs./acre oftotal potassium (as K2O). September 1 through October 30, 55 lbs./acreof total potassium (as K2O).

Calcium (as Ca) Profile:

35.00 lbs./acre Total Calcium. The calcium will be obtained from calciumnitrate solution (a non-co-reactant crop-quality enhancer). This is tobe added continuously during the following intervals: March 1 throughMay 31, 17.5 lbs./acre of total calcium (as Ca); June 1 through August31, 0 lbs./acre of total calcium (as Ca); September 1 through October30, 17.5 lbs./acre of total calcium (as Ca).

pH Profile:

Continuously adjust to a pH of 6.5 March 1 through October 30: The exactamount of sulfuric acid that is added is dependent on both thealkalinity resulting from the other crop-quality enhancers, as well asthe alkalinity of the irrigation water. This amount is determined by thepH controller, which always maintains the pH at the desired level. Inthis case the target pH is set at 6.5. (Note: Since sulfuric acid doesnot contain any nutrients it has no impact on the NPK levels.)

Charges and Nutrients Provided:

March 1 through May 31 Charges and Nutrients Provided:

Continuous simultaneous charge and reaction of the following co-reactantand non-co-reactant crop-quality enhancers: 50.60 lbs./acre ammonia,148.32 lbs./acre calcium nitrate, 194.52 lbs./acre nitric acid, 181.20lbs./acre urea, 73.68 lbs./acre phosphoric acid, 238.08 lbs./acrepotassium hydroxide and sulfuric acid (as required to maintain a targetpH of 6.5 for the treated irrigation water). This continuous chargeprovides: (a) 125 lbs./acre of total nitrogen (as N), equallydistributed between ammoniacal (41.68 lbs./acre), nitrate (41.68lbs./acre), and urea (41.68 lbs/acre) nitrogen; (b) 40.00 lbs./acrephosphate (as P2O5); 100.00 lbs./acre potassium (as K2O); and (d) 17.5lbs./acre calcium (as Ca).

June 1 through August 31 Charges and Nutrients Provided:

Continuous simultaneous charge and reaction of the following co-reactantcrop-quality enhancers: 10.11 lbs./acre ammonia, 55.16 lbs./acre nitricacid, 36.21 lbs./acre urea, 59.52 lbs./acre potassium hydroxide andsulfuric acid (as required to maintain a target pH of 6.5 for thetreated irrigation water). This continuous charge provides: (a) 24.99lbs./acre of total nitrogen (as N), equally distributed betweenammoniacal (8.33 lbs./acre), nitrate (8.33 lbs./acre), and urea (8.33lbs/acre) nitrogen; and (b) 25.00 lbs./acre potassium (as K2O).

September 1 through October 30 Charges and Nutrients Provided:

Continuous simultaneous charge and reaction of the following co-reactantand non-co-reactant crop-quality enhancers: 20.22 lbs./acre ammonia,148.30 lbs./acre calcium nitrate, 28.86 lbs./acre nitric acid, 72.42lbs./acre urea, 73.68 lbs./acre phosphoric acid, 130.96 lbs./acrepotassium hydroxide and sulfuric acid (as required to maintain a targetpH of 6.5 for the treated irrigation water). This continuous chargeprovides: (a) 49.98 lbs./acre of total nitrogen (as N), equallydistributed between ammoniacal (16.66 lbs./acre), nitrate (16.66lbs./acre), and urea (16.66 lbs/acre) nitrogen; (b) 40.00 lbs./acrephosphate (as P2O5); (c) 55.00 lbs./acre potassium (as K2O); and (d)17.50 lbs./acre calcium (as Ca).

Summary and Comments on Example 3 and Comparative Example C:

Fertilizers are the distinct formulations that are manufactured andconsist of electrically neutral, reacted compounds such as ammoniumnitrate, potassium sulfate, potassium ammonium phosphate and the like.In all the fertilizers manufactured by commercial producers or via themethod and system of the present invention, such neutral, reactedcompounds are manufactured, but once these fertilizer formulations arein solution such compounds all dissociate into anions, cations or remainas neutral species and it is these anions, cations and neutral speciesthat are the actual nutrients (fertilizer nutrients). Again, themacronutrients are N, P, K, or nitrogen, phosphorus and potassium.

As to the macronutrients, nitrogen (N) is the fertilizer nutrient thatis most complicated to provide because there are three forms, namely,urea-based nitrogen (urea), ammoniacal nitrogen (NH4+) and nitratenitrogen (NO3-). Urea and ammoniacal nitrogens must be broken down inthe soil (hydrolysis and/or oxidation) to nitrate (NO3-) nitrogen beforethey can be used by the plant. Phosphate's nutrient species are H2PO4,HPO4-2 and PO4-3. Potassium's nutrient species is K+.

As to the primary micronutrients, calcium's nutrient species is Ca+2 andmagnesium's micronutrient species is Mg+2.

As to other fertilizer components, the hydrogen (H+) cation is not anutrient or micronutrient but the pH of the soil (H+ concentration)affects the ability of the plant to absorb the nutrient species,including in particular the micronutrients. The sulfate anion SO4-2 ismostly inert and not considered a nutrient although plants may absorbsome sulfate for its S requirement. The thiosulfate anion S2O3-2 isinert and is rapidly oxidized to sulfate in the soil. The chloride anionis detrimental to plant growth and should be avoided if at all possible.

As seen above, there are just a few basic nutrients which can beobtained from fertilizer formulations.

Summary and Comments on Comparative Example C, March 1 through June 15

The March 1 fertigation used Structure® (Structure® is a registeredtrademark of Actagro, LLC of Biola, Calif.). Structure® as stated inComparative Example C is made from the following raw materials; ammonia,ammonium nitrate, urea, and phosphoric acid. When these raw materialsare reacted at the commercial fertilizer production plant the followingreactions take place to some extent until an equilibrium is reached:

-   -   1). NH4NO3—No reaction    -   2). Urea+H3PO4→[Urea][H3PO4]+heat of reaction    -   3). NH3+H3PO4→(NH4)H2PO4+ heat of reaction    -   4). 2NH3+H3PO4→(NH4)2HPO4+ heat of reaction    -   5). 3 NH3+H3PO4→(NH4)3PO4+ heat of reaction        In solution these transient reaction products immediately        dissociate into the following ionic and neutral species with the        formation of additional heat: (a) the cations NH4+ and H+; (b)        the anions NO3-, H2PO4-, HPO4-2 and PO4-3; and (c) the neutral        species urea, and these are the species which ultimately form        the basis of the nutrients that the plant uses.

The March 15 fertigation used K-Mend® (K-Mend® is a registered trademarkof Best Sulfur Products, Inc. of Fresno, Calif.) which, as stated in theComparative Example C, is potassium thiosulfate made from the followingraw materials; potassium sulfite and elemental sulfur. When these rawmaterials are reacted at the fertilizer plant the following reactiontakes place when heat is applied:

-   -   1). K2SO3+S+heat→K2S2O3        In solution this transient compound immediately dissociates into        the following ionic species: (a) the cation K+; and (b) the        anion S2O3-2. The potassium ion forms the basis for a potassium        nutrient while the thiosulfate anion eventually is oxidized to a        sulfate anion in the soil. Potassium thiosulfate, although        difficult to manufacture, provides one of the few potassium        salts that can be used as a fertilizer because of solubility        and/or compatibility reasons.

The March 30 fertigation used CAN-17 which, as stated in ComparativeExample C, is made from the following raw materials; calcium nitrate andammonium nitrate. When these raw materials are blended at the fertilizerplant the following reactions take place to some extent until anequilibrium is reached:

-   -   1). NH4NO3—No reaction    -   2). Ca(NO3)2—No reaction        In solution these transient compounds immediately dissociate        into the following ionic and neutral species with the formation        of additional heat: (a) the cations Ca+2 and NH4+; and (b) the        anion NO3-, and these are the species which ultimately form the        basis of the nutrients that the plant uses.

The April 15 fertigation used N-pHuric® which, as stated in ComparativeExample C, is made from the following raw materials: urea and sulfuricacid. When these raw materials are reacted at the fertilizer plant thefollowing reactions take place to some extent until an equilibrium isreached:

-   -   1). Urea+H2SO4→[Urea][H2SO4]+heat of reaction

In solution these transient compounds immediately dissociate into thefollowing ionic and neutral species with the formation of additionalheat: (a) the cation H+; (b) the anions HSO4- and SO4-2; and (c) neutralurea, and these are the species which ultimately form the basis of thenutrients that the plant uses.

The May 1 fertigation used Cache® (Cache® is a registered trademark ofActagro, LLC of Biola, Calif.) which, as stated in Comparative ExampleC, is made from the following raw materials; ammonia, ammonium nitrate,urea, phosphoric acid and potassium chloride. When these raw materialsare reacted at the fertilizer plant the following reactions take placeto some extent until an equilibrium is reached:

-   -   1). NH4NO3—No reaction    -   2). Urea+H3PO4→[Urea][H3PO4]+heat of reaction    -   3). NH3+H3PO4→(NH4)H2PO4+heat of reaction    -   4). 2NH3+H3PO4→(NH4)2HPO4+heat of reaction    -   5). 3 NH3+H3PO4→(NH4)3PO4+heat of reaction    -   6). KCl—No reaction        In solution these transient compounds immediately dissociate        into the following ionic and neutral species with the formation        of additional heat: (a) the cations NH4+, H+ and K+; (b) the        anions HPO4-2, H2PO4-, PO4-3 and Cl—; and (c) neutral urea, and        these are the species which ultimately form the basis of the        nutrients that the plant uses, except for chloride. The chloride        anion is not a fertilizer nor any kind of nutrient. It is        actually toxic for many crops. The reason why many commercial        formulations use potassium chloride is because there are few        potassium compounds that can be used as fertilizers because of        the limited solubility of potassium salts. As a result, except        for potassium thiosulfate, there are no viable potassium salts        that can be formulated into a potassium fertilizer. This is the        reason why potassium sulfate is rarely used as a fertilizer        because only very dilute solutions can be manufactured which        cause exorbitant shipping, storage and handling problems.

The May 15 fertigation used UAN 32 which, as stated in ComparativeExample C, is made from the following raw materials; ammonium nitrate,and urea. When these raw materials are reacted at the fertilizer plantthe following reactions take place to some extent until an equilibriumis reached:

-   -   1). NH4NO3—No reaction    -   2). Urea—No reaction        In solution these transient compounds immediately dissociate        into the following ionic and neutral species with the formation        of additional heat: (a) the cation NH4+; (b) the anion NO3-;        and (c) neutral urea, and these are the species which ultimately        form the basis of the nutrients that the plant uses.

The June 15 fertigation used K-Mend® (K-Mend® is a registered trademarkof Best Sulfur Products, Inc. of Fresno, Calif.) which is describedabove for the March 15 fertigation and therefore will not be repeatedhere.

Summary and Comments on Example 3, March 1 through June 15

In certain embodiments, the method and system of the present inventioncan use all or any of the concentrated raw materials that are used tomanufacture the above-described commercial fertilizers, namely ammonia,potassium hydroxide, urea, nitric acid, sulfuric acid, phosphoric acid,calcium nitrate and magnesium nitrate right at the irrigation site. Whenthese raw materials are reacted utilizing the irrigation system thefollowing reactions take place to some extent until an equilibrium isreached:

-   -   1). HNO3+KOH→KNO3+H2O+heat of reaction    -   2). HNO3+NH3→NH4NO3+heat of reaction    -   3). HNO3+urea→[urea][HNO3]+heat of reaction    -   4). H2SO4+KOH→KHSO4+H2O+heat of reaction    -   5). H2SO+2 KOH→K2SO4+2H2O+heat of reaction    -   6). H2SO4+NH3→(NH4)HSO4+heat of reaction    -   7). H2SO4+2NH3→(NH4)2SO4+heat of reaction    -   8). H2SO4+urea→[urea][H2SO4]+heat of reaction    -   9). H2SO4+2 urea→[urea]2-[H2SO4]+heat of reaction    -   10). H2SO4+KOH+NH3→K(NH4)SO4+H2O+heat of reaction    -   11). H3PO4+KOH→KH2PO4+H2O+heat of reaction    -   12). H3PO4+2 KOH→K2HPO4+2H2O+heat of reaction    -   13). H3PO4+3 KOH→K3PO4+3 H2O+heat of reaction    -   14). H3PO4+NH3→(NH4)H2PO4+heat of reaction    -   15). H3PO4+2NH3→(NH4)2HPO4+heat of reaction    -   16). H3PO4+3 NH3→(NH4)3PO4+heat of reaction    -   17). H3PO4+urea→[urea][H3PO4]+heat of reaction    -   18). H3PO4+NH3+KOH→K(NH4)HPO4+H2O+heat of reaction    -   19). H3PO4+2NH3+KOH→K(NH4)2PO4+H2O+heat of reaction    -   20). H3PO4+NH3+2 KOH→K2(NH4)PO4+2H2O+heat of reaction    -   21). Ca(NO3)2—No reaction    -   22). Mg(NO3)2—No reaction        In solution these transient compounds immediately dissociate        into the following ionic and neutral species with the formation        of additional heat: (a) the cations NH4+, H+, K+, Ca+2 and        Mg+2; (b) the anions NO3-, H2PO4-, HPO4-2, PO4-3; and (c)        neutral urea, and these are the species which ultimately form        the basis of the nutrients that the plant uses.

The continuous fertigations use the same crop-quality enhancers andratios throughout the time period or, if the growing conditions changed,the amounts and ratios of the nutrients, or other crop-qualityenhancer(s), being charged can be changed to best suit conditions at amoment's notice.

Summary and Comments on Comparative Example C, October 30 PotassiumAddition

As noted to a degree above, potassium thiosulfate was not availablecommercially, and therefore on October 30 no commercial fertilizerderived from potassium thiosulfate was available to the grower. As aresult of the unavailability of a commercial potassium thiosulfatefertilizer to meet the potassium requirements of the crop, the growerwas forced to have a fertilizer company manufacture a potassium sulfatefertilizer. Due to the low solubility of potassium sulfate, the growerhad to ship, store and fertigate with 1100.0 lbs./acre of a dilutepotassium sulfate fertilizer solution (0-0-5) which resulted in anextreme expense and inconvenience.

Summary and Comments on Comparative Example C and Example 3 MaterialUsage

As shown above, to provide the same N, P, K amounts, in ComparativeExample C the grower was required to have 1,291,324 lbs. of commercialfertilizer shipped to the site, while in Example 3 the grower was onlyrequired to have 689,376 lbs. of crop-quality enhancers shipped. Thisvast difference in shipping weights of 689,376 lbs for Example 3 versus1,291,324 lbs for Comparative Example C represents a 53.4% cost savingsin shipping for the grower.

Example 4 and Comparative Example D Projections

In a situation as described above for Example 3 and Comparative ExampleC, the same projections and profiles were set prior to the growingseason, but then excessive rainfall began and continued into the growingseason. Since the crop had already received an excessive amount ofwater, no irrigation or fertigation was done until the rainfalls ceasedand the soil sufficiently dried. When irrigation and fertigation couldcommence, it was no longer desirable to use the slow-release forms ofnitrogen, namely urea and ammoniacal nitrogen that are broken down inthe soil to nitrate nitrogen. Instead, fertigation with nitrate nitrogento provide nitrogen to the crop as quickly as possible was desired.

In the Comparative Example C situation, the grower intended to usecommercial fertilizers which provided a significant proportion ofslow-release forms of nitrogen on each of March 1, March 30, April 15,May 1, May 15 and June 1, and to assure that these fertilizers wereavailable when needed, the grower contracted in advance to purchasethese fertilizers in the quantities needed. The grower's options are toinitiate the late-season fertigations using the commercial fertilizersunder contract or fulfill its contractual obligations whileconcomitantly purchasing high nitrate-nitrogen fertilizer for actualuse. The first option is a poor choice for good crop growth, andtherefore has negative financial impacts, and the second option is alsoa poor choice financially.

In the Example 3 situation, the grower also intended to use acrop-quality-enhancer feedstock which included slow-release forms ofnitrogen, but since the fertilizer would be manufactured in situ fromcrop-quality enhancers that could be changed as to amount and proportionat will, that grower did not contract to purchase any fertilizers.

When fertigation could be initiated, the grower merely switched thecrop-quality-enhancer feedstock from one which provided a significantproportion of slow-release forms of nitrogen to one which provided theneeded nitrate nitrogen. The grower essentially has no burdenwhatsoever, and if additional quantities of crop-quality enhancers areneeded, the bulk transport thereof would be far less than the bulktransport of a high-nitrate-nitrogen commercial fertilizer.

In addition, to accommodate the reduced need for irrigation and theincreased need for nitrogen that can be taken up by the plant, as aresult of the heavy rainfall, the quantity (higher than the projectedamount to be added by the continuous fertigation beginning March 1) offast release nitrate nitrogen per unit time is simply and easilyincreased with the continuous fertigation. In a similar fashion, theother forms of nitrogen (ammoniacal and urea nitrogen) are decreased orstopped to provide the amount needed under the nitrogen profile with thecontinuous fertigation. Although the irrigation time is now shorter, theincrease in fast release nitrate nitrogen, when increased or adjusted inthis manner, quickly alleviates any nitrogen deficiency caused by theunexpected rainfall. This example demonstrates the versatility of thepresent invention (particularly but not limited to thein-situ-manufacturing embodiment) which rapidly corrects for anynutrient (N, P, K) deficiency by instantly changing the N, P, K profilewith no adverse impact on the crop or the grower.

Example 5 and Comparative Example E Projections

The method of the present invention in comparison to conventionalfertilization practices were evaluated for use at a 150 acre pistachioranch that has been using conventional fertilization practices foryears. For this comparison, a fertigation program similar to that usedin the past was selected for the projection of Comparative Example E.The projection of Example 5 is based on the same nutrients asComparative Example E at amounts that are approximately 25 percent lowerbecause, as discussed above, a far higher percentage of the nutrientsapplied are available to the crop in comparison to conventionalfertilization practices such as those of Comparative Example E. Theseprojections are shown in Table 10 below.

TABLE 10 Comparative Example E Example 5 Recommended RecommendedRecommended Nutrient Amount Amount Nitrogen (as N) 200 lb/acre as N 150lb/acre as N Phosphorus (as P2O5)  40 lb/acre as P2O5  30 lb/acre asP2O5 Potassium (as K2O) 150 lb/acre as K2O 120 lb/acre as K2O Calcium(as Ca)  50 lb/acre as Ca  35 lb/acre as Ca

The agricultural area of this Example 5 and Comparative Example E,namely the 150 acre pistachio ranch, will normally receive a total offour acre-feet of irrigation water over its eight-month (March 1 toNovember 1) growing season, delivered as follows: (a) 1.0 acre-footduring the first three months (March 1 through June 1); (b) 2.5acre-feet during the second three months (June 1 through September 1);and (c) 0.5 acre-foot during the last two months (September 1 throughNovember 1). An acre-foot is 325,851 gallons, and therefore 195.5million gallons of irrigation water are normally delivered to acreage ofthis ranch per growing season. The conventional fertigation program orschedule historically required on this pistachio ranch to meet thenutrient profile (shown again in Table 11 below) is shown in Table 12below. The fertigation program required using the method of the presentinvention to meet the adjusted nutrient profile (shown again in Table 13below) is shown in Table 14 below. The downward adjustment of thenutrient profile for the method of the present invention is a veryconservative estimate of the lower nutrient levels required whennutrients are no longer being lost to the root area as described abovefor conventional fertilization.

TABLE 11 Nutrient Profile Nutrient Total Nutrient Amount Nitrogen (as N)200 lb/acre Phosphorus (as P2O5)  40 lb/acre Potassium (as K2O) 150lb/acre Calcium (as Ca)  50 lb/acre

TABLE 12 Conventional Fertigation Schedule Amounts Slug Fed (lb./acre)Mar. Mar. Mar. Mar. Jun. Sep. Sep. Oct. Oct. 1 10 15 30 1 1 15 1 30Fertilizer Solution (% N-P-K & other nutrients) NH4H2PO4 (10-34-0) 73.544.1 UAN-32 (32-0-0) 263.6 22.8 CAN-17 (17-0-0) + 8.8 Ca 284.1 170.5113.6 K2S2O3 (0-0-25) 500.0 100.0 Nutrient by Type Nitrate nitrogen (asN) 20.43 32.96 19.78 13.18 1.77 Ammoniacal nitrogen (as N) 7.35 20.4315.34 9.21 6.13 1.77 4.41 Urea nitrogen (as N) 43.49 3.76 Phosphorus (asP2O5) 25.00 15.00 Potassium (as K2O) 125.0 25.00 Calcium (as Ca) 25.0015.00 10.00

TABLE 13 Adjusted Nutrient Profile Nutrient Total Nutrient AmountNitrogen (as N) 150 lb/acre Phosphorus (as P2O5)  30 lb/acre Potassium(as K2O) 120 lb/acre Calcium (as Ca)  35 lb/acre

TABLE 14 Continuous-Feed On-Site Manufacture Fertilization ScheduleTotal Amounts Fed Over Time Periods (lb.) Mar. Apr. May Jun. Jul. Aug.Sep. Oct. Fertilizer Solution (% N-P-K & other nutrients) NH4H2PO4 ←58.82 → ← 44.1 → (10-34-0) UAN-32 (32-0-0) ← 219.4 → ← 6.09 → CAN-17(17-0-0) + ← 170.5 → ← 113.6 → ← 113.6 → 8.8 Ca K2S2O3 (0-0-25) ← 400.0→ ← 80.0 → Nutrient (by type) Nitrate nitrogen ← 36.77 → ← 13.18 → ←13.65 → (as N) Ammoniacal ← 32.08 → ← 6.14 → ← 11.02 → nitrogen (as N)Urea nitrogen ← 36.17 → ← 1.0 → (as N) Phosphorus ← 20.00 → ← 10.00 →(as P2O5) Potassium ← 100.0 → ← 20.00 → (as K2O) Calcium (as Ca) ← 15.0→ ← 10.0 → ← 10.0 →

Projection Comparisons:

Slug Feed—Comparative Example E Projection (Nitrate Nitrogen):

On both March 10 and March 15 nitrate nitrogen (as N) is slug fed intothe irrigation system. Specifically, on March 10, 20.43 lbs./acrenitrate (as N) from a UAN-32 source is fed to 150 acres at a flow rateof 1200 gallons/min. for this grower's normal 9.0 hour irrigationperiod. (UAN is an acronym for an aqueous solution of urea and ammoniumnitrate.) The nitrate nitrogen (as N) concentration in the irrigationwater during this slug fertigation process is: (20.43 lbs./acre NO3- (asN)×150 acres×1000 grams/2.2 lbs.)/(1200 gal./min.×9 hrs.×60min./hr.×3.78 liters/gal.×1000 ml/l liter) or 569 ppm NO3- (as N).Specifically, on March 15, 32.96 lbs./acre nitrate (as N) from a CAN-17source is fed to 150 acres at a flow rate of 1200 gallons/min. for thisgrower's normal 9.0 hour irrigation period. (CAN is an acronym for anaqueous solution of calcium nitrate and ammonium nitrate.) The nitratenitrogen (as N) concentration in the irrigation water during this slugfertigation process is: (32.96 lbs./acre NO3- (as N)×150 acres×1000grams/2.2 lbs.)/(1200 gal./min.×9 hrs.×60 min./hr.×3.78 liters/gal.×1000ml/l liter) or 917 ppm NO3- (as N).

The amount of water used during each slug fertigation process is, usingthe parameter that an ac-ft (acre-foot) is 325,851 gallons of water:1200 gal./min.×60 min./hr.×9 hrs.=648,000 gal.×1 ac-ft/325,851 gal. or1.99 ac-ft.

The 1.99 ac-ft of water is distributed over 150 acres and therefore theper-acre water distribution (1.99 ac-ft/150 acres) is 0.0133 ac-ft/acre.The next nitrogen slug feed fertigation is June 1. The totalevenly-distributed irrigation water to be delivered during March, Apriland May is 1 ac-ft. Therefore the amount of irrigation water deliveredduring the period of March 16 (the day after the March 15th nitrogenslug feeding) and May 30 (the day before the June 1st slug feeding) isabout “1 ac-ft/acre×(2.5 months/3.0 months)” or 0.833 ac-ft/acre, and itwill contain no nitrate nitrogen fertilizer. Again, this grower's normalirrigation period is 9 hours per day. Therefore after the second nitrateslug feed of fertilizer there are about “[(0.833 ac-ft/acre)/(0.0133ac-ft/acre)-1]” or 61.6 irrigation periods (irrigation days) on which nonitrate nitrogen fertilizer is delivered with the irrigation water.

Continuous Feed—Example 5 Projection (Nitrate Nitrogen):

A total of 36.77 lbs./acre nitrate nitrogen is continuously charged tothe irrigation water distributed during each irrigation period duringthe months of March, April and May (from March 1 up to, but notincluding, June 1). For purposes of comparison to the slug-fedprojection above, only the nitrate nitrogen charged, and the irrigationwater delivered, during the shorter period of between March 15 and May30 is considered. The comparative (normalized) amount of nitratenitrogen is therefore 30.63 lbs./acre nitrate. The nitrate nitrogen (asN) concentration in the irrigation water during this continuousfertigation process is: (30.63 lbs./acre×150 acres×1000 grams/2.2lbs.)/(0.833 ac-ft/acre×325,851 gal./ac-ft×3780 ml/gal.×150 acres) or13.6 ppm NO3- (as N).

In other words, in this Example 5 projection, when the flow rate issufficient the fertilizer is added with irrigation water deliveredduring the 62.6 nine-hour irrigation periods from March 15 through May30, while in the Comparative Example E projection, the entire fertilizeris added only during two irrigation periods, each period being 9 hours,separated by 4 days namely March 10 and March 15, respectively.

Another difference between the slug feeding and the present invention'scontinuous feeding is the rate of fertilizer addition. To fullyillustrate the magnitude of this difference, the feed rate are providedbelow.

Slug Feed—Feed Rate of Comparative Example E Projection (NitrateNitrogen):

In the slug feeding projection of Comparative Example E, the nitratenitrogen source, on March 10 is a commercial UAN-32 which has a nitratecomposition of 7.75 percent nitrate nitrogen and a density of 11.06lbs./gal. (UAN is an acronym for an aqueous solution of urea andammonium nitrate.) The volume of UAN-32 used is: 150 acres×20.43lbs./acre NO3- (as N)×100%/7.75%×1 gal./11.06 lbs. or 3575 gallons. Thefeed rate of this 3575 gallons, which is fed in a 9.0 hr. irrigationperiod, is: 3575 gal./9.0 hrs.×1 hr./60 min. or 6.62 gal./min.(continuously throughout a nine hour irrigation period). Similarly, inthe slug feeding projection of Comparative Example E, the nitratenitrogen source, on March 15 is a commercial CAN-17 which has a nitratecomposition of 11.6 percent nitrate nitrogen and a density of 12.64lbs./gal. (CAN is an acronym for an aqueous solution of calcium nitrateand ammonium nitrate.) The volume of CAN-17 used is: 150 acres×32.96lbs./acre NO3- (as N)×100%/11.6%×1 gal./12.64 lbs. or 3372 gallons. Thefeed rate of this 3372 gallons, which is fed in a 9.0 hr. irrigationperiod, is: 3372 gal./9.0 hrs.×1 hr./60 min. or 6.24 gal./min.(continuously throughout a nine hour irrigation period).

Continuous Feed—Feed Rate of Example 5 Projection (Nitrate Nitrogen):

In the continuous feeding projection of Example 5 (again, the normalizedMarch 15 through May 30 feeding of 30.63 lbs./acre of nitrate nitrogen),the nitrate nitrogen is produced from two sources (again normalized):14.15 lbs./acre of nitrate nitrogen from the UAN-32 nitrate nitrogenfeedstock; and 16.48 lbs./acre of nitrate nitrogen from the CAN-17feedstock. These feedstocks have the following compositions anddensities, respectively: 7.75% nitrate nitrogen and a density of 11.06lbs./gal. and 11.6% nitrate nitrogen and a density of 12.64 lbs./gal.The volume of UAN-32 nitrate feedstock used is 150 acres×14.15 lbs./acreNO3- (as N)×100%/7.75%×1 gal./11.06 lbs. or 2476 gallons, which ischarged continuously during 62.6 irrigation periods at a feed rate of2476 gal./62.6 cycles×1 cycle/9.0 hrs.×1 hr./60 min. or 0.0732 gal./min.

The volume of CAN-17 nitrate feedstock used is 150 acres×16.48 lbs./acreNO3- (as N)×100%/11.6%×1 gal./12.64 lbs. or 1686 gallons, which ischarged continuously during 62.6 irrigation periods at a feed rate of1686 gal./62.6 cycles×1 cycle/9.0 hrs.×1 hr./60 min. or 0.0499 gal./min.

The same magnitude of differences between conventional slug-fedfertigation and the continuous fertigation of the present inventionexists for every fertilizer component and for every irrigationtime-period (March through May, June through August and the like). Thenitrate nitrogen exemplified here and others below are merely presentedfor illustration purposes.

Further, as seen from this comparison using nitrate nitrogen as anexample, the continuous fertigation of the present invention is far moreefficient and effective than conventional slug-fed fertigation becausethe crop is receiving the right level of fertilizer continuously and nofertilizer is being wasted. In addition, if after the start of theirrigation time period, the weather conditions change from thosepredicted or there is a change in the nutrient needs of the crops forany reasons, the continuous fertigation of the present invention can bereadily adjusted to levels appropriate for the altered needs, while nopost-time-period-start adjustments can be made in a slug-fed fertigationbecause all of the fertilizers have been added to the soil.

The impact of the system and method of the present invention are againreflected in the feed rates. Conventional slug-fed feed rate is 6.62gal./min. for a nitrate nitrogen addition of 20.43 lbs./acre for UAN-32on March 10 and conventional slug-fed rate is 6.24 gal./min. for nitrateaddition of 32.96 lbs./acre for CAN-17 on March 15. In contrast, usingthe system and method of the present invention, the feed rates are0.0732 gal./min. and 0.0499 gal./min. for nitrate nitrogen at a level of36.77 lbs./acre, whereby the slug-fed rate is 90.4 and 125.1 timeshigher respectively, although approximately the same amount nitratenitrogen is ultimately fed.

As seen in the above comparison, the system and method of the presentinvention can charge the fertilizer-nutrient feedstock to the irrigationsystem because so little fertilizer is being charged into the irrigationwater at any time interval that any exotherms or interaction between thefertilizers or interaction between the fertilizers and the hard alkalineirrigation water are dampened.

Slug Feed—Comparative Example E Projection (Potassium (as K2O)):

On March 30 potassium (as K2O) is slug fed into the irrigation system.Specifically, 125.0 lbs./acre potassium (as K2O) from a potassiumthiosulfate source is fed to 150 acres at a flow rate of 1200gallons/min. for this grower's normal 9.0 hour irrigation period. Thepotassium (as K2O) concentration in the irrigation water during thisslug fertigation process is: (125.0 lbs./acre potassium (as K2O)×150acres×1000 grams/2.2 lbs.)/(1200 gal./min.×9 hrs.×60 min./hr.×3.78liters/gal.×1000 ml/l liter) or 3,479 ppm potassium (as K2O). This highconcentration of potassium (as K2O) cannot be fed simultaneously with,or immediately after, the slug feeding of other fertilizers because ofthe incompatibilities with other fertilizers.

The amount of water used during this slug fertigation process is, usingthe parameter that an ac-ft (acre-foot) is 325,851 gallons of water:1200 gal./min.×60 min./hr.×9 hrs. or 648,000 gal.×1 ac-ft/325,851 gal.or 1.99 ac-ft. The 1.99 ac-ft of water is distributed over 150 acres andtherefore the per-acre water distribution (1.99 ac-ft/150 acres) is0.0133 ac-ft/acre.

The next slug feed fertigation of potassium is September 15. The totalevenly-distributed irrigation water to be delivered during April throughSeptember 15 is 3.292 ac-ft. Therefore the amount of irrigation waterdelivered during the period of April 1st (the day after the March 30thslug feeding) and September 14th (the day before the September 15th slugfeeding) is about “(1 ac-ft/acre×(2.0 months/3.0 months))+2.5ac-ft/acre+(0.5 ac-ft/acre×(0.5 month/2.0 months))” or 3.292 ac-ft/acre,and it will contain no potassium (as K2O) fertilizer. Again, thisgrower's normal irrigation period is 9 hours per day. Therefore afterthe single slug feed of fertilizer there are about “[(3.292ac-ft/acre)/(0.0133 ac-ft/acre)−1]” or 246.5 irrigation periods on whichno potassium (as K2O) fertilizer is delivered with the irrigation water.

Continuous Feed—Example 5 Projection (Potassium (as K2O)):

A total of 100.0 lbs./acre potassium (as K2O) is continuously charged ata low concentration (15.8 ppm potassium (as K2O) as shown below) to theirrigation water distributed during each irrigation period during themonths of March, April, May, June, and July (from March 1 up to, but notincluding, August 1). This low concentration of potassium (as K2O),unlike the high concentration slug fed as described above, can becharged simultaneously with other low-concentration fertilizerfeedstocks, and therefore this continuous feeding begins on the desiredMarch 1 date.

For purposes of comparison to the slug-fed projection above, only thepotassium (as K2O) charged, and the irrigation water delivered, duringthe time period of between March 30 and July 31 is compared. Thecomparative (normalized) amount of potassium (as K2O) charged betweenMarch 30 and July 31 is 100.0 lbs./acre potassium. The potassium (asK2O) concentration in the irrigation water during this continuousfertigation process is: (100.0 lbs./acre×150 acres×1000 grams/2.2lbs.)/(2.333 ac-ft/acre×325,851 gal./ac-ft×3780 ml/gal.×150 acres) or15.8 ppm potassium (as K2O).

In other words, in this Example 5 projection, potassium is continuouslydelivered with the 2.333 ac-ft of irrigation water delivered during the175.4 nine-hour irrigation periods from March 30 through July 31, whilein the Comparative Example E projection, the entire fertilizer is addedonly during the first nine-hour irrigation period. Further, thepotassium (as K2O) charged in Example 5 is 25% less than in ComparativeExample E because, given the rate of potassium uptake by a plant, this75% lower amount is sufficient to maintain a constant supply ofpotassium in the wetted root zone throughout the March 1 through July 31time period. In contrast, the higher amount of potassium is required inComparative Example E to at least partially compensate for the amount ofpotassium in the single slug feeding that is later washed away from thewetted root zone before uptake by a plant.

Again, another difference between the slug feeding of ComparativeExample E and the present invention's continuous feeding of Example 5 isthe rate of fertilizer addition. Again to fully illustrate the magnitudeof this difference, the feed rate are provided below.

Slug Feed—Feed Rate of Comparative Example E Projection (Potassium (asK2O)):

In the slug feeding projection of Comparative Example E, the source ofthe 125 lbs./acre of potassium (as K2O) is a potassium thiosulfate(K2SSO3) feedstock which is 25.0 percent potassium (as K2O) and has adensity of 12.64 lbs./gal. The volume of the potassium thiosulfatefeedstock used is: 150 acres×125.0 lbs./acre potassium (asK2O)×100%/25.0%×1 gal./12.64 lbs. or 5934 gallons. This 5934 gallons isthen applied to the 150 acres in a 9.0 hr. period which means the feedrate is: 5934 gal./9.0 hrs.×1 hr./60 min.=10.99 gal./min. (continuouslythroughout a nine hour irrigation period).

Continuous Feed—Feed Rate of Example 5 Projection (Potassium (as K2O)):

In the continuous feeding projection of Example 5, which again will beillustrated as the normalized (March 30 through July 31) feeding of100.0 lbs. of potassium (as K2O), the source being potassium thiosulfatehaving 25% potassium (as K2O) and a density of 12.64 lb./acre. Thevolume of potassium thiosulfate feedstock used is: 150 acres×100lbs./acre potassium (as K2O)×100%/25%×1 gal./12.64 lbs. or 4747 gallons.

The feed rate of this 4747 gallons, which is charged continuously fordelivery to 150 acres 175.4 nine-hour irrigation periods, is: 4747gal./175.4 periods×1 period/9.0 hrs.×1 hr./60 min. or 0.0501 gal./min.

Therefore the feed rate of the present invention's Example 5 projectionis 0.0501/10.99, or 0.46%, that of the feed rate of the ComparativeExample E projection. In other words, the feed rate of the ComparativeExample E projection is 10.99/0.0501, or 219.4% faster than the feedrate of the present invention's Example 5 projection. In other words,the conventional slug-feeding feed rate is 10.99 gal./min. for apotassium addition of 125.0 lbs./acre (as K2O), the continuous-feed feedrate of the present invention is 0.0501 gal./min. for a potassiumaddition 100.0 lbs./acre (as K2O), and therefore the slug-feed is (10.99gal./min)/(0.0501 gal./min.) or 219 times faster.

Continuous Feed—Responsive to Shifting Conditions, Example 5 Projection(Potassium (as K2O)):

Although this Example 5 projection for potassium (and likewise any ofthe chemicals being added or produced) for a distinct irrigation period,it is easily seen that if the weather changes or a crops need changestheir nutrient profile for any reason, the method and system of thepresent invention is, or preferably is, responsive to those changes. Incontrast, once a single shot (slug feeding) of fertilizer is deliveredto the crop as in the conventional method (such as shown in ComparativeExample E), no responsive changes can be made because everything hasalready added to the soil. The method of the present invention, unlikethe conventional slug feeding method, is not locked in to any feed rateof components. In other words, any blend can be injected at any timeproviding the best fertigation profile with absolutely no waste becausethe fertilizer is injected exactly when the crop needs it, instead ofmeeting equipment and labor constraints as occurs with the slug feedapproach.

Slug Feed—Comparative Example E Projection (Calcium, Phosphorus):

This projection does not take into account the water-quality factor,which is discussed separately below.

On March 15 calcium (as Ca) is slug fed into the irrigation system.Specifically, 25.00 lbs./acre calcium (as Ca) from a CAN-17 source isfed to 150 acres at a flow rate of 1200 gallons/min. for this grower'snormal 9.0 hour irrigation period. (CAN is an acronym for an aqueoussolution of calcium nitrate and ammonium nitrate.) The calcium (as Ca)concentration in the irrigation water during this slug fertigationprocess therefore is: (25.00 lbs./acre calcium (as Ca)×150 acres×1000grams/2.2 lbs.)/(1200 gal./min.×9 hrs.×60 min./hr.×3.78 liters/gal.×1000ml/l liter) or 695.9 ppm calcium (as Ca). The amount of water usedduring this slug fertigation process is, using the parameter that anac-ft (acre-foot) is 325,851 gallons of water: 1200 gal./min.×60min./hr.×9 hrs. or 648,000 gal.×1 ac-ft/325,851 gal. or 1.99 ac-ft.

The 1.99 ac-ft of water is distributed over 150 acres and therefore theper-acre water distribution (1.99 ac-ft/150 acres) is 0.0133 ac-ft/acre.The next slug feed fertigation is June 1. The total evenly-distributedirrigation water to be delivered during March, April, and May is 1ac-ft. Therefore the amount of irrigation water delivered during theperiod of March 16th (the day after the March 15th slug feeding) and May30 (the day before the June 1 slug feeding) is about “1 ac-ft/acre×(2.5months/3.0 months)” or 0.833 ac-ft/acre, and it will contain no CAN-17fertilizer. Again, this grower's normal irrigation period is 9 hours perday. Therefore after the single slug feed of fertilizer there are about“[(0.833 ac-ft/acre)/(0.0133 ac-ft/acre)−1]” or 61.6 irrigation periodson which no calcium fertilizer is delivered with the irrigation water.

As seen from the above, the calcium and phosphorus fertilizers are slugfed on different days, namely the calcium fertilizer on March 15, June 1and September 1, and the phosphorus fertilizer on March 1 and October30. These fertilizers are not slug fed simultaneously because theslug-fed calcium concentration is vastly higher than the threshold levelbeyond which precipitation will occur when added together withphosphate. In more detail, when added as shown above, namely 25.00lbs/acre calcium (as Ca) with a water usage of 0.0133 ac-ft/acre onMarch 15, 15.00 lbs./acre calcium (as Ca) with a water usage of 0.0133ac-ft/acre on June 1 and 10.00 lbs./acre calcium (as Ca) with a waterusage of 0.0133 ac-ft/acre on September 1, the calcium addition rate is695.9 ppm calcium (as Ca) or 1740 ppm (as CaCO3) on March 15, 417.5 ppmcalcium (as Ca) or 1044 ppm (as CaCO3) on June 1 and 278.4 ppm calcium(as Ca) or 695.9 ppm (as CaCO3) on September 1. (Using the samecalculation method, the addition rate of 25.00 lbs/acre phosphate (asP2O5) on March, 1 and 15.00 lbs/acre phosphate (as P2O5) on October 30is 931.1 ppm PO4-3 and 558.7 ppm PO4-3, respectively.)

For the first injection of a phosphate fertilizer the maximum amount ofcalcium that can be present in the irrigation water concomitantly withthat phosphate-based fertilizer, at a water pH of 6.5, is 2.5 ppmcalcium (as Ca). For the second injection of a phosphate fertilizer themaximum amount of calcium that can be present in the irrigation waterconcomitantly with that phosphate-based fertilizer, at a water pH of6.5, is 4.2 ppm calcium (as Ca). The 695.9 ppm (as Ca) addition rate isabout 278 times higher than that threshold for the first injection ofphosphate fertilizer. The 278.4 ppm (as Ca) addition rate is about 66.3times higher than that threshold for the second injection of phosphatefertilizer. Even if the addition rates were lowered by 50% via calciumadditions on six rather than three fertigation days and the phosphatefour rather than two irrigation days, the calcium addition rate wouldstill be vastly higher than the solubility threshold.

Continuous Feed—Example 5 Projection (Calcium):

This projection does not take into account the water-quality factor,which is discussed separately below.

These projections are first set out here as if the phosphate additionduring the various time periods did not occur. The profile withphosphate addition are described thereafter.

A total of 15.00 lbs./acre of calcium (as Ca) is continuously charged tothe irrigation water distributed during each irrigation period duringthe months of March, April and May (from March 1 up to, but notincluding, June 1). It is noted that any fertilizer feedstock andtherefore the calcium is delivered to the crop at the time it is needed,and not merely when a tank or manpower is available as seen whenconventional slug-fed fertigation techniques are used. The presentinvention is also illustrated below in this Example 5 for the subsequentirrigation periods that have a different water usage.

The calcium (as Ca) concentration in the irrigation water during thecontinuous fertigation process from March 1 through May 31 (a 1.0ac-ft/acre water usage period) is: (15.00 lbs./acre×150 acres×1000grams/2.2 lbs.)/(1.0 ac-ft/acre×325,851 gal./ac-ft×3780 ml/gal.×150acres) or 5.54 ppm calcium (as Ca).

The calcium (as Ca) concentration in the irrigation water during thecontinuous fertigation process from June 1 through August 31 (a 2.5ac-ft/acre water usage period) is: (10.00 lbs./acre×150 acres×1000grams/2.2 lbs.)/(2.5 ac-ft/acre×325,851 gal./ac-ft×3780 ml/gal.×150acres) or 1.48 ppm calcium (as Ca).

The calcium (as Ca) concentration in the irrigation water during thecontinuous fertigation process from September 1 through October 31 (a0.5 ac-ft/acre water usage period) is: (10.00 lbs./acre×150 acres×1000grams/2.2 lbs.)/(0.5 ac-ft/acre×325,851 gal./ac-ft×3780 ml/gal.×150acres) or 7.38 ppm calcium (as Ca).

In this projection, and in the system and method of the presentinvention generally, the rate of chemical addition does notautomatically change when the irrigation water usage or flow ratechanges (unless the system is programmed to do so). When the amount offertilizer (here, calcium (as Ca)) delivered during a 9 hour irrigationperiod is held constant regardless of the water usage, the concentrationof calcium (as Ca) in the irrigation water is lower when the volume ofirrigation water delivered during a 9 hour irrigation period is higher,as seen here for the from June 1 through August 31 time period.Similarly, the concentration of calcium (as Ca) in the irrigation wateris higher when the volume of irrigation water delivered during a 9 hourirrigation period is lower, as seen here for the from September 1through October 31 time period. This is an important distinction becausethis is the period where the plant/crop requires less or no nutrients,and a lower fertilizer level can be added providing better usage of thefertilizer by the plant as well as better economics. Unlike conventionalfertigation methods, any of the fertilizer nutrients or crop-qualityenhancers and any combinations of these nutrients or crop-qualityenhancers can be charged simultaneously using the system and the methodof the present invention provided that no solubility limits areexceeded.

Further, the calcium charged in this projection is less than inComparative Example E because, given the rate of calcium uptake by aplant, this lower amount is sufficient to maintain a constant supply ofcalcium in the wetted root zone throughout the time period. In contrast,the higher amounts of calcium are required in Comparative Example E toat least partially compensate for the amount of calcium in the singleslug feeding and mechanical application respectively which is laterwashed away from the wetted root zone before uptake by a plant.

Again, as mentioned elsewhere herein, the system and method of thepresent invention substantially eliminate the problems that arise fromincompatibilities between fertilizers because solubility limitsgenerally cannot be exceeded when feeding continuously at low levels.When conventional slug-feeding fertigation methods are used, thesolubility limits between incompatible fertilizers are exceeded, andtherefore such fertilizers must be fed on different days, and then onlyafter washing out the feeding equipment. As an example, calciumfertilizers normally form very insoluble calcium phosphates in thepresence of phosphate fertilizers, and therefore calcium fertilizerscannot be slug fed together phosphate fertilizers; doing so would causemassive, catastrophic plugging of the entire irrigation system.

Continuous Feed—Example 5 Projection (Calcium, Phosphorus):

The Example 5 calcium projections above provide the amount of calcium tobe added continuously, and the concentrations of calcium in theirrigation water for two levels of water usage (volume of irrigationwater per acre delivered to the soil in a nine-hour irrigation period)when calcium is continuously charged. Those concentrations of calcium(continuously charged) are used in this projection as the basis orgroundwork for the calculation of calcium concentrations when fed atcyclic (recurring) intervals to avoid incompatibilities with phosphate.

This projection provides a profile regarding the calcium feedingsimultaneously with a phosphate crop-quality enhancer, which would becharged as follows. From March 1 up to, but not including, June 1, theaddition of 20.00 lb/acre phosphate (as P2O5), given a water usage of1.00 ac-ft/acre, provides a concentration of 9.88 ppm PO4-3 in theirrigation water. From September 1 up to, but not including, November 1,the addition of 10.00 lb/acre phosphate (as P2O5), given a water usageof 0.50 ac-ft/acre, provides a concentration of 9.88 ppm PO4-3 in theirrigation water.

When simultaneously feeding both a calcium and the above-indicatedamount of phosphate crop-quality enhancer at a water pH of 6.5 using themethod and system of the present invention, the maximum amount ofcalcium that can be present in the irrigation water is 124 ppm calcium(as Ca). Exceeding that maximum will, due to calcium/phosphateinteraction and/or precipitation, lead to plugging of the irrigationsystem. As indicated above, the calcium (as Ca) concentration in theirrigation water is 5.54 ppm calcium (as Ca) during the continuousfertigation process from March 1 through May 31 and is 7.38 ppm calcium(as Ca) during the continuous fertigation process from September 1through October 31. (There is no addition of phosphate June throughAugust.) The calcium-concentration threshold above which there is airrigation-system plugging problem, is twenty-two times higher than thehighest calcium concentration used in this projection during the periodof March 1 through May 31 and is seventeen times higher than the highestcalcium concentration used in this projection during the period ofSeptember 1 through October 31.

Slug Feed—Comparative Example E Projection (Calcium, Phosphorus, WaterQuality):

The irrigation water at this site contains 60 ppm calcium (as Ca). Asnoted in the slug-feed projection above, calcium and phosphorus are fedon separate fertigation days to avoid interactions/precipitation arisingfrom calcium and phosphate concentrations. That projection disregardedthe 60 ppm calcium (as Ca) already present in the irrigation water.

The profile above provides fertigations on March 1 and October 30 thatfeed 928.4 ppm phosphate (as PO4-3) and 556.9 ppm phosphate (as PO4-3),respectively. No calcium is fed on these dates because the calciumsolubility threshold is 5.54 ppm calcium (as Ca) and 7.38 ppm (as Ca),respectively. The 60 ppm calcium (as Ca) already present in theirrigation water is much higher than the 5.54 ppm (as Ca) and 7.38 ppmcalcium (as Ca) threshold values, and therefore if that profile wasfollowed, precipitation and plugging of the irrigation system wouldoccur despite the precaution of not simultaneously slug feeding calciumand phosphate.

Continuous Feed—Example 5 Projection (Calcium, Phosphorus, WaterQuality):

As noted above, the irrigation water at this site contains 60 ppmcalcium (as Ca). As noted in the projection above, the continuous feedmethod and system of the present invention provides a concentration of9.88 ppm PO4-3 in the irrigation water from March 1 up to, but notincluding, June 1, and a concentration of 9.88 ppm PO4-3 in theirrigation water from September 1 up to, but not including, November 1.The calcium concentration thresholds for these time periods are both124.1 ppm calcium (as Ca) and the calcium concentrations from thecontinuous fertigations are 5.54 and 7.38 ppm calcium (as CaCO3)respectively. The addition of 60 ppm calcium (as Ca) already present inthe irrigation water raises the calcium concentrations to about 65.5 and67.4 ppm calcium (as Ca) respectively, which remain well below thethresholds of 124.1 ppm calcium (as Ca). In other words, despite thehigh calcium levels in the irrigation water itself, the continuous feedmethod and system of the present invention permits calcium and phosphateto be charged to the irrigation system simultaneously because thecalcium-concentration threshold is about 1.9 times higher than theactual calcium concentration from March 1 up to, but not including, June1, and the calcium-concentration threshold is about 1.8 times higherthan the actual calcium concentration from is September 1 up to, but notincluding, November 1.

Examples 6-11 Micronutrient Augmented Feedstocks

The projections of Examples 15 through 20 exemplifymicronutrient-augmented prolonged-termed crop-quality-enhancementfertigation for six separate agricultural sites, including post-harvestfertigation prior to the crop cycles in five of the Examples. Theamounts of the macronutrient-crop-quality-enhancer raw materials thatare fed, and the amounts of micronutrient raw materials and specificmicronutrients that are fed, for each example, each in terms of lb/acreof an element or defined moiety, per month for each fertigation month,are set forth below in Tables 17-22. The macronutrient raw materials(“Mac-RM”) are described in Table 15 below and the micronutrient rawmaterials (Mic-RM) are described in Table 16 below. In Tables 17 to 22,the abbreviation “t-Me” means “total metals” (total micronutrients) andis used to delineate the total amount of micronutrient charged based onactives. The total amount of each micronutrient added during the cropcycles, or combined post-harvest and crop cycles of Examples 6-8, 10 and11, for each of Examples 6 to 11, are set out in Table 23 below. The pHof the fertigation water was adjusted to a pH of 6.5 in each of Examples6 to 11.

TABLE 15 Macronutrient Raw Material (“RM”) No. Description Mac-1 A blendof ammonium nitrate and urea which contains 32.0% nitrogen (as N),namely 7.75% ammoniacal nitrogen (slow release nitrogen), 7.75% nitratenitrogen (fast release nitrogen, calcium salt), and 16.5% urea nitrogen(very slow release nitrogen) Mac-2 A blend of ammonium nitrate and ureawhich contains 32.0% nitrogen (as N), namely 7.75% ammoniacal nitrogen(slow release nitrogen), 7.75% nitrate nitrogen (fast release nitrogen),and 16.5% urea nitrogen (very slow release nitrogen) Mac-3 Concentratedphosphoric acid solution (NPK of 0-42-0) Mac-4 Concentrated potassiumhydroxide solution (NPK of 0-0-42)

TABLE 16 Micronutrient Micronutrients in Raw Material Percentage Order(“RM”) No. (highest to lowest) Mic-1 Fe, Mn, Zn, Mg, B and Cu saltsMic-2 Fe, Mn, Zn, Mg, Cu, Mo and Co salts Mic-3 Fe, Mn, Zn, Mg, B, Cu,Mo and Co salts Mic-4 Fe and Zn salts Mic-5 Zn, Fe, Mn, Mg, B and Cusalts Mic-6 Fe salts

TABLE 17 Example 6 Raw Material and Amount (in lb/acre) Mac-1 Mac-1Mac-2 Mac-3 Mac-4 Mic-1 Month(s) (as N) (as Ca) (as N) (as P2O5) (asK2O) (as t-Me) Oct.-Nov. 35 18.1 — 40 45 0.355 Dec.-Jan. — — — — — —Feb. 30 15.5 — 22.5 20 0.473 Mar. 40 20.7 — 22.5 30 1.419 Apr. — — 40 1550 0.355 May — — 35 10 50 0.355 Jun. — — 15 — 30 0.355 Jul. — — 10 — 250.355 Aug.-Sep. — — — — — —

TABLE 18 Example 7 Raw Material and Amount (in lb/acre) Mac-1 Mac-1Mac-2 Mac-3 Mac-4 Mic-2 Month(s) (as N) (as Ca) (as N) (as P2O5) (asK2O) (as t-Me) Oct.-Nov. — — 30 25 40 0.170 Dec.-Jan. — — — — — — Feb.50 25.8 — 25 40 0.170 Mar. 50 25.8 — 25 50 0.170 Apr. 50 25.8 20 25 600.170 May — — 50 — 40 0.170 Jun. — — — — 30 0.170 Jul. — — — — — 0.170Aug.-Sep. — — — — — —

TABLE 19 Example 8 Raw Material and Amount (in lb/acre) Mac-1 Mac-1Mac-2 Mac-3 Mac-4 Mic-3 Month(s) (as N) (as Ca) (as N) (as P2O5) (asK2O) (as t-Me) Oct.-Nov. — — 35 25 30 0.332 Dec.-Jan. — — — — — — Feb.50 25.8 — 25 30 .332 Mar. 50 25.8 — 25 30 .332 Apr. — — 50 15 50 0.332May — — 50 15 50 0.332 Jun. — — 10 — 30 0.332 Jul. — — 5 — 15 —Aug.-Sep. — — — — — —

TABLE 20 Example 9 Raw Material and Amount (in lb/acre) Mac-1 Mac-1Mac-2 Mac-3 Mac-4 Mic-4 Month(s) (as N) (as Ca) (as N) (as P2O5) (asK2O) (as t-Me) Jan. — — — — — — Feb. 10 5.2 — 10 10 0.250 Mar. 25 12.9 —15 25 0.250 Apr. 25 12.9 — 15 25 0.250 May 25 12.9 — 15 25 0.250 Jun. 2512.9 — 15 25 0.250 Jul. 25 12.9 — 15 25 0.250 Aug. 25 12.9 — 15 25 0.250Sep. 25 12.9 — 15 25 0.250 Oct.-Dec. — — — — — —

TABLE 21 Example 10 Raw Material and Amount (in lb/acre) Mac-1 Mac-1Mac-2 Mac-3 Mac-4 Mic-5 Month(s) (as N) (as Ca) (as N) (as P2O5) (asK2O) (as t-Me) Sep. 15- 35 18.1 — 20 10 0.142 Nov. Dec.- — — — — — —Jan. Feb. 25 12.9 — 15 10 0.213 Mar. 65 33.6 — 20 40 0.426 Apr. 75 38.8— 15 50 0.142 May 85 44 — 10 50 0.142 Jun. 15 7.8 — — 20 0.142 Jul.-Sep. 14

TABLE 22 Example 11 Raw Material and Amount (in lb/acre) Mac-1 Mac-1Mac-2 Mac-3 Mac-4 Mic-6 Month(s) (as N) (as Ca) (as N) (as P2O5) (asK2O) (as t-Me) Oct.-Nov. 35 18.1 — 40 45 0.286 Dec.-Jan. — — — — — —Feb. 30 15.5 — 22.5 20 0.286 Mar. 40 20.7 — 22.5 30 0.286 Apr. — — 40 1550 0.286 May — — 35 10 50 0.286 Jun. — — 15 — 30 0.286 Jul. — — 10 — 250.286 Aug.-Sep. — — — — — —

TABLE 23 Total Macronutrients and Micronutrients Added (all in lb/acre)Ex. 6 Ex. 7 Ex. 8 Ex. 9 Ex. 10 Ex. 11 Macronutrients N (as N) 205 250250 185 300 205 Ca (as Ca) 54.3 77.4 51.6 95.5 155.3 54.3 P (as P2O5)110 80 100 110 80 110 (K (as K2O) 250 260 225 185 180 250 MicronutrientsFe 0.772 0.310 0.310 0.667 0.600 2.000 Mn 0.772 0.310 0.310 1.333 0.254— Zn 1.823 0.310 0.310 — 0.254 — Mg 0.234 0.050 0.050 — 0.077 — B 0.052— 0.800 — 0.017 — Cu 0.012 0.150 0.150 — 0.004 — Mo — 0.030 0.030 — — Co— 0.030 0.030 —In these six examples (Examples 6-11), crop-quality-enhanced fertigationover four to six months during crop cycles, and in some, but not all,instances over one and a half to two months after the prior harvest, forthe benefit of the subsequent crop cycle, are shown. In each example,one or more micronutrients are included in the feedstock together withmacronutrients over the fertigation period, or part thereof, and inExample 7 micronutrient addition is continued beyond macronutrientaddition. The micronutrients preferably are charged in an availableform, such as soluble salts and chelates, and are charged at levelsbelow the precipitation threshold. The present invention in someembodiments is a system for prolonged-termed continuouscrop-quality-enhancement fertigation of an agricultural field under theirrigation of an active agricultural irrigation system. Suchprolonged-termed continuous crop-quality-enhancement fertigationincludes charging a crop-quality-enhancer feedstock to the activeagricultural irrigation system, wherein the active agriculturalirrigation system has flowing irrigation water upstream of theagricultural field. The crop-quality-enhancer feedstock is comprised ofone or more crop-quality enhancers (which are also referred to herein asraw materials and which may, but need not be, co-reactants). Thecrop-quality-enhancer feedstock may be comprised of (a) a plurality ofco-reactant crop-quality enhancers (which are also referred to herein asco-reactants), (b) one or more non-co-reactant crop-quality enhancers(which are also referred to herein as non-co-reactants) and (c)combinations thereof, and such co-reactant and non-co-reactantcrop-quality enhancers generate an exotherm upon intermixing with theirrigation water and, at times, upon intermixing with each other.

The system for prolonged-termed continuous crop-quality-enhancementfertigation has at least one, and possibly a plurality of,crop-quality-enhancer feed point(s) open to a stream of flowingirrigation water. The feed points (when there is a plurality of feedpoints) are sufficiently proximate each other and the stream of theirrigation water has sufficient flow to intermix the crop-qualityenhancer(s) with the stream of flowing irrigation water. (The generationof dissolution exotherm(s) and any reaction exotherm would, of course,be experienced as merely an exotherm.) The feed points (when there are aplurality of feed points) are each preferably spaced-apart from theneighboring feed point(s) a distance of no more than about 10 inches,and more preferably no more than about 8 inches because, in preferredembodiments, the pH of the post-feed (treated) irrigation water ismonitored upstream of the agricultural field. The length of the mainlinealong which such pH monitoring occurs might be twenty to thirty feet, orit might be only a few feet. In the former instances, closely proximatefeed points and the positioning of the feed points well upstream of thepH monitoring point allows a good intermixing of the crop-qualityenhancers ahead of the pH monitoring point. In the latter instances,closely proximate feed points positioned as far upstream of the pHmonitoring point as practically possible are needed to provide areasonable degree of intermixing of the crop-quality enhancers ahead ofthe monitoring point.

The stream of irrigation water also has a sufficient flow to dampen thedissolution exotherm(s) and any reaction exotherm(s). Such dissolutionand reaction exotherms generally raise the temperature of the waterwhich receives the crop-quality enhancer(s). In an irrigation system,the ambient temperature of the irrigation water depends on a number offactors, including the time of year (which impacts ambient outdoors airtemperature) and the ambient temperature of the water source (whichvaries from very cold water, such as snow run-off, to rather warm water,such as well water in geothermal areas) and it can range from 35 to 100degrees F. An excessive, and in instances dangerous, increase in watertemperature would ensue if the irrigation water were static or had aninsufficient flow to dampen the exotherm(s). A sufficient flow isdifficult to adequately describe in terms of flow rates becausemain-line diameters and other factors differ drastically from oneirrigation system to another. Therefore the sufficiency of flow isbetter described in terms of its ability to dissipate the heat of theexotherms, which in turn is measurable by the increase, if any, in theambient water temperature of the irrigation water. In the presentinvention generally, an increase in temperature over ambient watertemperature (which again can be very cold to rather warm) is no morethan about 60 degrees F. and is dependent on the co-reactants being fed,and rate at which they are being fed, and individual characteristics ofthe irrigation system being served. In preferred embodiments thedissolution exotherm(s) and any reaction exotherm(s) are dampened to theextent that a temperature increase is no more than 40 degrees F. overambient irrigation water temperature, and more preferably no more than20 degrees F. over ambient irrigation water temperature.

The system of the present invention has means for separately andsimultaneously feeding at least one, and possibly a plurality of,crop-quality-enhancer(s) to the stream of flowing irrigation waterwhereby treated irrigation water is formed. As described above for thesystems shown in FIG. 1 to FIG. 4, such means can include feed lines,each running from a supply of a crop-quality enhancer to a feed point,and the various controls described for activating and maintaining thefeeding of a crop-quality enhancer, and in certain embodiments thesimultaneous feeding of crop-quality enhancers, to the stream of flowingirrigation water. Upon the feeding of the crop-quality enhancer(s) tothe stream of flowing irrigation water, the crop-quality enhancersintermix with the irrigation water and any included additionalcrop-quality enhancers, and in certain embodiments react anddisassociate as described above, and convert the irrigation water totreated irrigation water (the irrigation water now being a vehiclecarrying the crop-quality enhancer(s) to the agricultural field).

The present invention does not exclude, but is not limited to,simultaneously feeding two or more co-reactant crop-quality-enhancerswith or without one or more non-co-reactant crop-quality-enhancer. Everyco-reactant would be a crop-quality enhancer co-reactant with at leastone other crop-quality-enhancer being simultaneously fed or it would notbe a co-reactant crop-quality-enhancer as that term is used herein.

The irrigation system includes means for irrigating the agriculturalfield with the treated irrigation water, which means are the transportpipe lines and micro-irrigation type of emitters or the like, oroverhead sprinkling systems.

The crop-quality-enhancer feed point(s) preferably open to ahigh-dilution environment and therefore the crop-quality enhancer(s) arefed to a high-dilution environment. Feeding to such a high-dilutionenvironment is preferred because a greater dampening of exotherms willbe realized. Embodiments of the system of the present invention in whichthe crop-quality enhancer(s) are fed to a high-dilution environmentinclude feeding to the stream of flowing irrigation water flowingthrough the main line of an irrigation system at a section upstream ofthe agricultural field, and in such embodiments the feed point(s) aredisposed along the main line. Embodiments of the system of the presentinvention in which the crop-quality enhancer(s) are fed to ahigh-dilution environment also include feeding to a stream of irrigationwater flowing through a side-arm mixing chamber (which discharges to themain line) and then the feed point(s) are disposed along the side-armmixing chamber. In the latter instance, the fast flow and discharge tothe main line are a sufficiently high-dilution environment to dampenexotherms although monitoring the water temperature in this region isprudent while monitoring water temperature in the former embodiments canbe unnecessary.

In preferred embodiments, the system of the present invention includesmeans to commence the feed of crop-quality enhancer(s) upon the waterstream reaching a first pre-selected degree of flow, means to halt thefeed upon the stream reaching a second pre-selected degree of flow, andmeans to separately provide a pre-selected degree of feed through eachof the feed point(s), such as the components described above for thesystems shown in FIG. 1 through FIG. 4.

In preferred embodiments, the system of the present invention includesmeans to determine the pH of the treated irrigation water upstream ofthe agricultural field, such as the components described above for thesystems shown in FIG. 1 through FIG. 4. The point for determining the pHof the treated irrigation water is of course downstream of the feedpoint(s) because irrigation water is converted to treated irrigationwater only upon receiving the crop-quality enhancer(s). Preferably thepH of the treated irrigation water has sufficient time to stabilizeprior to being monitored and therefore the monitoring of the pH, or thesampling for the pH monitoring, is as far downstream of the feedpoint(s) as practicalities permit. For this same reason, namely to spaceapart the feed point(s) and pH monitoring point, the feed points, whenthere are a plurality of feed points, are preferably close to eachother, for instance no more than about ten inches apart from adjacentfeed points. A distance between adjacent feed points of from about sixto about eight inches is very practical. When the length of main lineavailable is only about three feet, the feed point(s) are preferablyplaced as far upstream as possible and the pH monitoring point is placedas far downstream as practical so as to leave the longest stretch ofline between them as is practical. When the length of available mainline is thirty-five feet, it is still desirable to place the feedpoint(s) well upstream and the pH monitoring point well downstream foroptimal pH stabilization.

The method of the present invention preferably uses the system of thepresent invention. The method of the present invention is a method ofprolonged-termed continuous crop-quality-enhancement fertigation of anagricultural field. This method is practiced or implemented only for anactive irrigation system having flowing irrigation water upstream of theagricultural field. In broad embodiments of the present invention, themethod comprises the steps of: (step 1) continuously charging acrop-quality-enhancer feedstock comprised of at least one crop-qualityenhancer to the active agricultural irrigation system by sub-step 1a andoptionally sub-step 1b of: (sub-step 1a) continuously charging a firstcrop-quality enhancer to a stream of flowing irrigation water upstreamof the agricultural field at a first feed point; and (sub-step 1b)simultaneously charging a second crop-quality enhancer to the stream offlowing irrigation water at a second feed point. The stream of flowingirrigation water has sufficient flow to intermix the crop-qualityenhancer(s) with the irrigation water, generating at least onedissolution exotherm and possibly at least one reaction exotherm. Thestream of flowing irrigation water has sufficient flow to dampen thedissolution (and any reaction) exotherm(s). The irrigation water isconverted to treated irrigation water. Then (step 2) the agriculturalfield is irrigated with the treated irrigation water. In preferredembodiments, the flow of the stream of flowing irrigation water issufficient to dampen the dissolution (and any reaction) exotherm(s) to amaximum temperature increase of 40 degrees F. over ambient irrigationwater temperature, and more preferably 20 degrees F. over ambientirrigation water temperature. In various preferred embodiments themethod includes, in sub-steps 1a, and optionally sub-step 1b, chargingof the first, and possibly and second or more crop-quality enhancer(s)to a high-dilution environment, such as charging of the first, or more,crop-quality enhancer(s) to the main line and charging to a side-armmixing chamber that discharges to the main line.

In preferred embodiments of the method of the present invention, whenthe crop-quality enhancers are available in concentrated form, they areused in concentrated form, for instance sulfuric acid in an aqueoussolution containing from 50 to 98 wt. percent sulfuric acid, or anaqueous solution containing from 50 to 71 wt. percent nitric acid orphosphoric acid in an aqueous solution containing from 65 to 85 wt.percent phosphoric acid, or potassium hydroxide as a 35 to 50 wt.percent aqueous solution, urea as a 40 to 50 wt. percent aqueoussolution, ammonium hydroxide as a 20 to 29 wt. percent aqueous solutionand ammonia as a 95 to 100 wt. percent gas.

In other preferred embodiments, the method further includes the steps ofselecting a target pH, determining the pH of the treated irrigationwater, and charging an acid to the stream of flowing irrigation water inan amount sufficient to adjust the pH of the treated irrigation water toa target pH.

In preferred embodiments, the methods described above further explicitlyinclude a crop-quality-enhancer feedstock that includes one or moremicronutrient-crop-quality enhancers such as Fe, Mn, Zn, Mg, B, Cu, Moand Co salts and chelants thereof.

While the foregoing written description of the invention enables one ofordinary skill in the art to make and use the invention, and to make anduse what is presently considered the best mode of the invention, thoseof ordinary skill in the art will understand and appreciate theexistence of variations, combinations and equivalents of the specificembodiments, methods and examples provided herein. The present inventionshould not be limited by the above described embodiments, methods andexamples.

We claim:
 1. A method of prolonged-termed crop-quality-enhancementfertigation of an agricultural field, said agricultural field beingirrigated by means of an active irrigation system having a stream offlowing irrigation water upstream of said agricultural field, saidmethod comprising the steps of: (step 1) converting said irrigationwater to treated irrigation water by continuously charging acrop-quality-enhancer feedstock comprised of a first crop-qualityenhancer, a second crop-quality enhancer and amicronutrient-crop-quality enhancer to said stream of flowing irrigationwater at respectively a first feed point, a second feed point and athird feed point, generating a dissolution exotherm, wherein said firstcrop-quality enhancer is selected from the group consisting of sulfuricacid in an aqueous solution containing from 50 to 98 wt. percentsulfuric acid, nitric acid in an aqueous solution containing from 50 to71 wt. percent nitric acid and phosphoric acid in an aqueous solutioncontaining from 65 to 85 wt. percent phosphoric acid, wherein saidsecond crop-quality enhancer is selected from the group consisting ofpotassium hydroxide as a 35 to 50 wt. percent aqueous solution, urea asa 40 to 50 wt. percent aqueous solution, ammonium hydroxide as a 20 to29 wt. percent aqueous solution and ammonia as a 95 to 100 wt. percentgas, wherein said stream of flowing irrigation water has sufficient flowto intermix said crop-quality enhancer with said irrigation water anddampen said dissolution exotherm; (step 2) irrigating said agriculturalfield with said treated irrigation water; and (step 3) repeating step 1and step 2 each irrigation day over a prolonged term.
 2. The method ofprolonged-termed crop-quality-enhancement fertigation of an agriculturalfield of claim 1 wherein said micronutrient-crop-quality enhancer isselected from the group consisting of Fe, Mn, Zn, Mg, B, Cu, Mo, Co andsalts and chelants thereof.
 3. The method of prolonged-termedcrop-quality-enhancement fertigation of an agricultural field of claim 1wherein said flow of said stream of flowing irrigation water issufficient to dampen said dissolution exotherm to a maximum temperatureincrease of 20 degrees F. over ambient irrigation water temperature. 4.The method of prolonged-termed crop-quality-enhancement fertigation ofan agricultural field of claim 1 wherein said agricultural irrigationsystem includes a main line upstream of said agricultural field, andwherein said charging of said crop-quality-enhancer feedstock to saidstream of flowing irrigation water is a charging of saidcrop-quality-enhancer feedstock to said main line.
 5. The method ofprolonged-termed crop-quality-enhancement fertigation of an agriculturalfield of claim 1, wherein said prolonged term is from 75 to 100 percentof a crop cycle.
 6. A method of prolonged-termedcrop-quality-enhancement fertigation of an agricultural field under theirrigation of an active agricultural irrigation system using acontinuous crop-quality-enhancement fertigation system, said activeagricultural irrigation system having a stream of flowing irrigationwater upstream of said agricultural field, a main line and a side-armmixing chamber off said main line, wherein said stream of flowingirrigation water is flowing through said side-arm mixing chamber anddischarging to said main line, said crop-quality-enhancement fertigationsystem having a first feed point and a second feed point, said first andsecond feed points being disposed along said side-arm mixing chamber andopen to said stream of flowing irrigation water, wherein said stream offlowing irrigation water has sufficient flow to intermix a firstcrop-quality enhancer and a micronutrient-crop-quality enhancer withsaid stream of flowing irrigation water, generating at least onedissolution exotherm, and wherein said stream of flowing irrigationwater has sufficient flow to dampen said dissolution exotherm, and meansfor feeding said first crop-quality enhancer and saidmicronutrient-crop-quality enhancer to said stream of flowing irrigationwater whereby treated irrigation water is formed, wherein saidagricultural irrigation system includes means for irrigating saidagricultural field with said treated irrigation water, said methodcomprising the steps of: (step 1) continuously feeding acrop-quality-enhancer feedstock comprised of said first crop-qualityenhancer and said micronutrient-crop-quality enhancer at respectivelysaid first feed point and said second feed point to said stream offlowing irrigation water flowing through said side-arm mixing chamberand discharging to said main line at levels within the system solubilitylimits, whereby said irrigation water is converted to treated irrigationwater; (step 2) irrigating said agricultural field with said treatedirrigation water; and (step 3) repeating step 1 and step 2 eachirrigation day over a prolonged term.
 7. The method of prolonged-termedcrop-quality-enhancement fertigation of an agricultural field of claim 6wherein said prolonged term is from 75 to 100 percent of a crop cycle.8. The method of prolonged-termed crop-quality-enhancement fertigationof an agricultural field of claim 6 wherein said system further includesmeans to regulate the feed of said first crop-quality enhancer and thefeed of said micronutrient-crop-quality enhancer being fed to saidstream of flowing irrigation water through respectively said first feedpoint and said second feed point, including means to commence said feedupon said stream reaching a first pre-selected degree of flow, means tohalt said feed upon said stream reaching a second pre-selected degree offlow, and means to provide a pre-selected degree of feed through saidfeed point, wherein, in said step 1, said continuous feeding of saidfirst crop-quality enhancer and said micronutrient-crop-quality enhancercommences upon said stream reaching a first pre-selected degree of flowand halts upon said stream reaching a second pre-selected degree offlow.
 9. The method of prolonged-termed crop-quality-enhancementfertigation of an agricultural field of claim 6, wherein saidmicronutrient-crop-quality enhancer is selected from the groupconsisting of Fe, Mn, Zn, Mg, B, Cu, Mo and Co salts and chelantsthereof.
 10. The method of prolonged-termed crop-quality-enhancementfertigation of an agricultural field of claim 6, wherein saidmicronutrient-crop-quality enhancer is selected from the groupconsisting of Fe, Mn, Zn, Mg and B salts and chelants thereof.
 11. Themethod of prolonged-termed crop-quality-enhancement fertigation of anagricultural field of claim 6, wherein said crop-quality-enhancerfeedstock includes a second crop-quality enhancer and wherein said firstcrop-quality enhancer and said second crop-quality enhancer arerespectively sulfuric acid in an aqueous solution containing from 50 to98 wt. percent sulfuric acid and a crop-quality enhancer selected fromthe group consisting of potassium hydroxide as a 35 to 50 wt. percentaqueous solution, urea as a 40 to 50 wt. percent aqueous solution,ammonium hydroxide as a 20 to 29 wt. percent aqueous solution andammonia as a 95 to 100 wt. percent gas.
 12. The method ofprolonged-termed crop-quality-enhancement fertigation of an agriculturalfield of claim 6, wherein said crop-quality-enhancer feedstock includesa second crop-quality enhancer and wherein said first crop-qualityenhancer and said second crop-quality enhancer are respectively nitricacid in an aqueous solution containing from 50 to 71 wt. percent nitricacid and a crop-quality enhancer selected from the group consisting ofpotassium hydroxide as a 35 to 50 wt. percent aqueous solution, urea asa 40 to 50 wt. percent aqueous solution, ammonium hydroxide as a 20 to29 wt. percent aqueous solution and ammonia as a 95 to 100 wt. percentgas.
 13. The method of prolonged-termed crop-quality-enhancementfertigation of an agricultural field of claim 6, wherein saidcrop-quality-enhancer-feedstock includes a second crop-quality enhancerand wherein said first crop-quality enhancer and said secondcrop-quality enhancer are respectively phosphoric acid in an aqueoussolution containing from 65 to 85 wt. percent phosphoric acid and acrop-quality enhancer selected from the group consisting of potassiumhydroxide as a 35 to 50 wt. percent aqueous solution, urea as a 40 to 50wt. percent aqueous solution, ammonium hydroxide as a 20 to 29 wt.percent aqueous solution and ammonia as a 95 to 100 wt. percent gas. 14.The method of prolonged-termed crop-quality-enhancement fertigation ofan agricultural field of claim 6 wherein said flow of said stream offlowing irrigation water is sufficient to dampen said dissolutionexotherm to a maximum temperature increase of 20 degrees F. over ambientirrigation water temperature.
 15. A method of prolonged-termedcrop-quality-enhancement fertigation of an agricultural field, saidagricultural field being irrigated by means of an active irrigationsystem having a stream of flowing irrigation water upstream of saidagricultural field, said method comprising the steps of: (step 1)converting said irrigation water to treated irrigation water bycontinuously charging a crop-quality-enhancer feedstock comprised of afirst crop-quality enhancer, a second crop-quality enhancer and amicronutrient-crop-quality enhancer to said stream of flowing irrigationwater at respectively a first feed point, a second feed point and athird feed point, wherein said first, second and third feed points aresufficiently proximate each other and wherein said stream of saidirrigation water has sufficient flow to intermix said first crop-qualityenhancer, said second crop-quality enhancer and saidmicronutrient-crop-quality enhancer with each other and with saidirrigation water, generating at least one dissolution exotherm, whereinsaid stream of flowing irrigation water has sufficient flow to intermixsaid crop-quality enhancer with said irrigation water and dampen saiddissolution exotherm; (step 2) irrigating said agricultural field withsaid treated irrigation water; and (step 3) repeating step 1 and step 2each irrigation day over a prolonged term.
 16. The method ofprolonged-termed crop-quality-enhancement fertigation of an agriculturalfield of claim 15 wherein said first feed point and said second feedpoint are spaced apart a maximum of ten inches.
 17. The method ofprolonged-termed crop-quality-enhancement fertigation of an agriculturalfield of claim 15 wherein said prolonged term is from 75 to 100 percentof a crop cycle.
 18. The method of prolonged-termedcrop-quality-enhancement fertigation of an agricultural field of claim15 wherein said flow of said stream of flowing irrigation water issufficient to dampen said dissolution exotherm to a maximum temperatureincrease of 20 degrees F. over ambient irrigation water temperature. 19.The method of prolonged-termed crop-quality-enhancement fertigation ofan agricultural field of claim 15 wherein said agricultural irrigationsystem includes a main line upstream of said agricultural field, andwherein said charging of said crop-quality-enhancer feedstock to saidstream of flowing irrigation water is a charging of saidcrop-quality-enhancer feedstock to said main line.
 20. The method ofprolonged-termed crop-quality-enhancement fertigation of an agriculturalfield of claim 15, wherein said micronutrient-crop-quality enhancer isselected from the group consisting of Fe, Mn, Zn, Mg, B, Cu, Mo and Cosalts and chelants thereof.